Migrate grpc to null safety (#432)

.github/workflows/dart.yml

@@ -11,12 +11,12 @@ on:
 
 jobs:
   # Check code formating and static analysis on a single OS (linux)
-  # against Dart stable and dev.
+  # against Dart dev.
   analyze:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        sdk: [stable, dev]
+        sdk: [dev]
     steps:
       - uses: actions/checkout@v2
       - uses: cedx/setup-dart@v2
@@ -43,7 +43,7 @@ jobs:
 
   # Run tests on a matrix consisting of three dimensions:
   # 1. OS: mac, windows, linux
-  # 2. release channel: stable, dev
+  # 2. release channel: dev
   # 3. TODO: Dart execution mode: native, web
   test:
     needs: analyze
@@ -51,7 +51,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        sdk: [stable, dev]
+        sdk: [dev]
         platform: [vm, chrome]
         exclude:
           # We only run Chrome tests on Linux. No need to run them

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 3.0.0-nullsafety.0
+
+* Migrate library and tests to null safety.
+
 ## 2.9.0
 
 * Added support for compression/decompression, which can be configured through

example/googleapis/pubspec.yaml

@@ -9,7 +9,7 @@ dependencies:
   async: ^2.2.0
   grpc:
     path: ../../
-  protobuf: ^1.0.1
+  protobuf: ^2.0.0-nullsafety
 
 dev_dependencies:
   test: ^1.6.4

example/grpc-web/pubspec.yaml

@@ -8,8 +8,7 @@ environment:
 dependencies:
   grpc:
     path: ../../
-  protobuf: ^1.0.1
+  protobuf: ^2.0.0-nullsafety
 
 dev_dependencies:
   build_runner: ^1.5.2
-  build_web_compilers: ^2.1.1

example/helloworld/pubspec.yaml

@@ -9,4 +9,4 @@ dependencies:
   async: ^2.2.0
   grpc:
     path: ../../
-  protobuf: ^1.0.1
+  protobuf: ^2.0.0-nullsafety

example/metadata/pubspec.yaml

@@ -9,7 +9,7 @@ dependencies:
   async: ^2.2.0
   grpc:
     path: ../../
-  protobuf: ^1.0.1
+  protobuf: ^2.0.0-nullsafety
 
 dev_dependencies:
   test: ^1.6.0

example/route_guide/pubspec.yaml

@@ -9,4 +9,4 @@ dependencies:
   async: ^2.2.0
   grpc:
     path: ../../
-  protobuf: ^1.0.1
+  protobuf: ^2.0.0-nullsafety

interop/pubspec.yaml

@@ -11,7 +11,7 @@ dependencies:
   collection: ^1.14.11
   grpc:
     path: ../
-  protobuf: ^1.0.1
+  protobuf: ^2.0.0-nullsafety
 
 dev_dependencies:
   test: ^1.6.4

lib/src/auth/auth.dart

@@ -20,25 +20,26 @@ import 'package:googleapis_auth/auth.dart' as auth;
 import 'package:http/http.dart' as http;
 
 import '../client/call.dart';
-import '../shared/status.dart';
 import 'rsa.dart';
 
 const _tokenExpirationThreshold = Duration(seconds: 30);
 
 abstract class BaseAuthenticator {
-  auth.AccessToken _accessToken;
+  auth.AccessToken? _accessToken;
-  String _lastUri;
+  late String _lastUri;
+  var _lastUriSet = false;
 
   Future<void> authenticate(Map<String, String> metadata, String uri) async {
-    if (uri == null) {
+    if (_accessToken == null ||
-      throw GrpcError.unauthenticated('Credentials require secure transport.');
+        _accessToken!.hasExpired ||
-    }
+        !_lastUriSet ||
-    if (_accessToken == null || _accessToken.hasExpired || uri != _lastUri) {
+        uri != _lastUri) {
       await obtainAccessCredentials(uri);
       _lastUri = uri;
+      _lastUriSet = true;
     }
 
-    final auth = '${_accessToken.type} ${_accessToken.data}';
+    final auth = '${_accessToken!.type} ${_accessToken!.data}';
     metadata['authorization'] = auth;
 
     if (_tokenExpiresSoon) {
@@ -47,7 +48,7 @@ abstract class BaseAuthenticator {
     }
   }
 
-  bool get _tokenExpiresSoon => _accessToken.expiry
+  bool get _tokenExpiresSoon => _accessToken!.expiry
       .subtract(_tokenExpirationThreshold)
       .isBefore(DateTime.now().toUtc());
 
@@ -57,7 +58,7 @@ abstract class BaseAuthenticator {
 }
 
 abstract class HttpBasedAuthenticator extends BaseAuthenticator {
-  Future<void> _call;
+  Future<void>? _call;
 
   Future<void> obtainAccessCredentials(String uri) {
     if (_call == null) {
@@ -68,7 +69,7 @@ abstract class HttpBasedAuthenticator extends BaseAuthenticator {
         authClient.close();
       });
     }
-    return _call;
+    return _call!;
   }
 
   Future<auth.AccessCredentials> obtainCredentialsWithClient(
@@ -77,18 +78,21 @@ abstract class HttpBasedAuthenticator extends BaseAuthenticator {
 
 class JwtServiceAccountAuthenticator extends BaseAuthenticator {
   auth.ServiceAccountCredentials _serviceAccountCredentials;
-  String _projectId;
+  String? _projectId;
-  String _keyId;
+  String? _keyId;
 
-  JwtServiceAccountAuthenticator(String serviceAccountJson) {
+  JwtServiceAccountAuthenticator.fromJson(
-    final serviceAccount = jsonDecode(serviceAccountJson);
+      Map<String, dynamic> serviceAccountJson)
-    _serviceAccountCredentials =
+      : _serviceAccountCredentials =
-        auth.ServiceAccountCredentials.fromJson(serviceAccount);
+            auth.ServiceAccountCredentials.fromJson(serviceAccountJson),
-    _projectId = serviceAccount['project_id'];
+        _projectId = serviceAccountJson['project_id'],
-    _keyId = serviceAccount['private_key_id'];
+        _keyId = serviceAccountJson['private_key_id'];
-  }
 
-  String get projectId => _projectId;
+  factory JwtServiceAccountAuthenticator(String serviceAccountJsonString) =>
+      JwtServiceAccountAuthenticator.fromJson(
+          jsonDecode(serviceAccountJsonString));
+
+  String? get projectId => _projectId;
 
   Future<void> obtainAccessCredentials(String uri) async {
     _accessToken = _jwtTokenFor(_serviceAccountCredentials, _keyId, uri);
@@ -97,8 +101,8 @@ class JwtServiceAccountAuthenticator extends BaseAuthenticator {
 
 // TODO(jakobr): Expose in googleapis_auth.
 auth.AccessToken _jwtTokenFor(
-    auth.ServiceAccountCredentials credentials, String keyId, String uri,
+    auth.ServiceAccountCredentials credentials, String? keyId, String uri,
-    {String user, List<String> scopes}) {
+    {String? user, List<String>? scopes}) {
   // Subtracting 20 seconds from current timestamp to allow for clock skew among
   // servers.
   final timestamp =

lib/src/auth/auth_io.dart

@@ -13,18 +13,22 @@ class ComputeEngineAuthenticator extends HttpBasedAuthenticator {
 }
 
 class ServiceAccountAuthenticator extends HttpBasedAuthenticator {
-  auth.ServiceAccountCredentials _serviceAccountCredentials;
+  late auth.ServiceAccountCredentials _serviceAccountCredentials;
   final List<String> _scopes;
-  String _projectId;
+  String? _projectId;
 
-  ServiceAccountAuthenticator(String serviceAccountJson, this._scopes) {
+  ServiceAccountAuthenticator.fromJson(
-    final serviceAccount = jsonDecode(serviceAccountJson);
+      Map<String, dynamic> serviceAccountJson, this._scopes)
-    _serviceAccountCredentials =
+      : _serviceAccountCredentials =
-        auth.ServiceAccountCredentials.fromJson(serviceAccount);
+            auth.ServiceAccountCredentials.fromJson(serviceAccountJson),
-    _projectId = serviceAccount['project_id'];
+        _projectId = serviceAccountJson['project_id'];
-  }
 
-  String get projectId => _projectId;
+  factory ServiceAccountAuthenticator(
+          String serviceAccountJsonString, List<String> scopes) =>
+      ServiceAccountAuthenticator.fromJson(
+          jsonDecode(serviceAccountJsonString), scopes);
+
+  String? get projectId => _projectId;
 
   Future<auth.AccessCredentials> obtainCredentialsWithClient(
           http.Client client, String uri) =>
@@ -35,7 +39,7 @@ class ServiceAccountAuthenticator extends HttpBasedAuthenticator {
 class _CredentialsRefreshingAuthenticator extends HttpBasedAuthenticator {
   final auth.ClientId _clientId;
   auth.AccessCredentials _accessCredentials;
-  final String _quotaProject;
+  final String? _quotaProject;
 
   _CredentialsRefreshingAuthenticator(
     this._clientId,
@@ -47,7 +51,7 @@ class _CredentialsRefreshingAuthenticator extends HttpBasedAuthenticator {
     await super.authenticate(metadata, uri);
     if (_quotaProject != null) {
       // https://cloud.google.com/apis/docs/system-parameters#definitions
-      metadata['X-Goog-User-Project'] = _quotaProject;
+      metadata['X-Goog-User-Project'] = _quotaProject!;
     }
   }
 
@@ -83,8 +87,8 @@ class _CredentialsRefreshingAuthenticator extends HttpBasedAuthenticator {
 Future<HttpBasedAuthenticator> applicationDefaultCredentialsAuthenticator(
   List<String> scopes,
 ) async {
-  File credFile;
+  File? credFile;
-  String fileSource;
+  String? fileSource;
   // If env var specifies a file to load credentials from we'll do that.
   final credsEnv = Platform.environment['GOOGLE_APPLICATION_CREDENTIALS'];
   if (credsEnv != null && credsEnv.isNotEmpty) {
@@ -97,10 +101,10 @@ Future<HttpBasedAuthenticator> applicationDefaultCredentialsAuthenticator(
   // Attempt to use file created by `gcloud auth application-default login`
   File gcloudAdcFile;
   if (Platform.isWindows) {
-    gcloudAdcFile = File.fromUri(Uri.directory(Platform.environment['APPDATA'])
+    gcloudAdcFile = File.fromUri(Uri.directory(Platform.environment['APPDATA']!)
         .resolve('gcloud/application_default_credentials.json'));
   } else {
-    gcloudAdcFile = File.fromUri(Uri.directory(Platform.environment['HOME'])
+    gcloudAdcFile = File.fromUri(Uri.directory(Platform.environment['HOME']!)
         .resolve('.config/gcloud/application_default_credentials.json'));
   }
   // Only try to load from gcloudAdcFile if it exists.

lib/src/auth/rsa.dart

@@ -99,7 +99,7 @@ class ASN1Parser {
   static const SEQUENCE_TAG = 0x30;
 
   static ASN1Object parse(Uint8List bytes) {
-    invalidFormat(String msg) {
+    Never invalidFormat(String msg) {
       throw new ArgumentError("Invalid DER encoding: $msg");
     }
 
@@ -185,8 +185,6 @@ class ASN1Parser {
           invalidFormat(
               'Unexpected tag $tag at offset ${offset - 1} (end: $end).');
       }
-      // Unreachable.
-      return null;
     }
 
     final obj = decodeObject();

lib/src/client/call.dart

@@ -38,6 +38,7 @@ const _reservedHeaders = [
   'grpc-encoding',
   'user-agent',
 ];
+const _statusDetailsHeader = 'grpc-status-details-bin';
 
 /// Provides per-RPC metadata.
 ///
@@ -55,9 +56,9 @@ typedef FutureOr<void> MetadataProvider(
 /// Runtime options for an RPC.
 class CallOptions {
   final Map<String, String> metadata;
-  final Duration timeout;
+  final Duration? timeout;
   final List<MetadataProvider> metadataProviders;
-  final Codec compression;
+  final Codec? compression;
 
   CallOptions._(
     this.metadata,
@@ -73,10 +74,10 @@ class CallOptions {
   /// invoked in order for every RPC, and can modify the outgoing metadata
   /// (including metadata provided by previous providers).
   factory CallOptions({
-    Map<String, String> metadata,
+    Map<String, String>? metadata,
-    Duration timeout,
+    Duration? timeout,
-    List<MetadataProvider> providers,
+    List<MetadataProvider>? providers,
-    Codec compression,
+    Codec? compression,
   }) {
     return CallOptions._(
       Map.unmodifiable(metadata ?? {}),
@@ -89,7 +90,7 @@ class CallOptions {
   factory CallOptions.from(Iterable<CallOptions> options) =>
       options.fold(CallOptions(), (p, o) => p.mergedWith(o));
 
-  CallOptions mergedWith(CallOptions other) {
+  CallOptions mergedWith(CallOptions? other) {
     if (other == null) return this;
     final mergedMetadata = Map.from(metadata)..addAll(other.metadata);
     final mergedTimeout = other.timeout ?? timeout;
@@ -116,16 +117,16 @@ class WebCallOptions extends CallOptions {
   /// For this to work correctly, a proxy server must be set up that
   /// understands the query parameter and can unpack/send the original
   /// list of headers to the server endpoint.
-  final bool bypassCorsPreflight;
+  final bool? bypassCorsPreflight;
 
   /// Whether to send credentials along with the XHR.
   ///
   /// This may be required for proxying or wherever the server
   /// needs to otherwise inspect client cookies for that domain.
-  final bool withCredentials;
+  final bool? withCredentials;
   // TODO(mightyvoice): add a list of extra QueryParameter for gRPC.
 
-  WebCallOptions._(Map<String, String> metadata, Duration timeout,
+  WebCallOptions._(Map<String, String> metadata, Duration? timeout,
       List<MetadataProvider> metadataProviders,
       {this.bypassCorsPreflight, this.withCredentials})
       : super._(metadata, timeout, metadataProviders, null);
@@ -136,11 +137,11 @@ class WebCallOptions extends CallOptions {
   /// metadata [providers] of [CallOptions], [bypassCorsPreflight] and
   /// [withCredentials] for CORS request.
   factory WebCallOptions(
-      {Map<String, String> metadata,
+      {Map<String, String>? metadata,
-      Duration timeout,
+      Duration? timeout,
-      List<MetadataProvider> providers,
+      List<MetadataProvider>? providers,
-      bool bypassCorsPreflight,
+      bool? bypassCorsPreflight,
-      bool withCredentials}) {
+      bool? withCredentials}) {
     return WebCallOptions._(Map.unmodifiable(metadata ?? {}), timeout,
         List.unmodifiable(providers ?? []),
         bypassCorsPreflight: bypassCorsPreflight ?? false,
@@ -148,7 +149,7 @@ class WebCallOptions extends CallOptions {
   }
 
   @override
-  CallOptions mergedWith(CallOptions other) {
+  CallOptions mergedWith(CallOptions? other) {
     if (other == null) return this;
 
     final mergedMetadata = Map.from(metadata)..addAll(other.metadata);
@@ -163,11 +164,9 @@ class WebCallOptions extends CallOptions {
           withCredentials: withCredentials);
     }
 
-    final otherOptions = other as WebCallOptions;
     final mergedBypassCorsPreflight =
-        otherOptions.bypassCorsPreflight ?? bypassCorsPreflight;
+        other.bypassCorsPreflight ?? bypassCorsPreflight;
-    final mergedWithCredentials =
+    final mergedWithCredentials = other.withCredentials ?? withCredentials;
-        otherOptions.withCredentials ?? withCredentials;
     return WebCallOptions._(Map.unmodifiable(mergedMetadata), mergedTimeout,
         List.unmodifiable(mergedProviders),
         bypassCorsPreflight: mergedBypassCorsPreflight,
@@ -185,28 +184,28 @@ class ClientCall<Q, R> implements Response {
   final _trailers = Completer<Map<String, String>>();
   bool _hasReceivedResponses = false;
 
-  Map<String, String> _headerMetadata;
+  late Map<String, String> _headerMetadata;
 
-  GrpcTransportStream _stream;
+  GrpcTransportStream? _stream;
-  StreamController<R> _responses;
+  final _responses = StreamController<R>();
-  StreamSubscription<List<int>> _requestSubscription;
+  StreamSubscription<List<int>>? _requestSubscription;
-  StreamSubscription<GrpcMessage> _responseSubscription;
+  StreamSubscription<GrpcMessage>? _responseSubscription;
 
   bool isCancelled = false;
-  Timer _timeoutTimer;
+  Timer? _timeoutTimer;
 
-  final TimelineTask _requestTimeline;
+  final TimelineTask? _requestTimeline;
-  TimelineTask _responseTimeline;
+  TimelineTask? _responseTimeline;
 
   ClientCall(this._method, this._requests, this.options,
       [this._requestTimeline]) {
     _requestTimeline?.start('gRPC Request: ${_method.path}', arguments: {
       'method': _method.path,
-      'timeout': options?.timeout?.toString(),
+      'timeout': options.timeout?.toString(),
     });
-    _responses = StreamController(onListen: _onResponseListen);
+    _responses.onListen = _onResponseListen;
     if (options.timeout != null) {
-      _timeoutTimer = Timer(options.timeout, _onTimedOut);
+      _timeoutTimer = Timer(options.timeout!, _onTimedOut);
     }
   }
 
@@ -251,7 +250,7 @@ class ClientCall<Q, R> implements Response {
       final metadata = Map<String, String>.from(options.metadata);
       Future.forEach(
               options.metadataProviders,
-              (provider) => provider(metadata,
+              (MetadataProvider provider) => provider(metadata,
                   '${connection.scheme}://${connection.authority}${audiencePath(_method)}'))
           .then((_) => _sendRequest(connection, _sanitizeMetadata(metadata)))
           .catchError(_onMetadataProviderError);
@@ -263,8 +262,9 @@ class ClientCall<Q, R> implements Response {
   }
 
   void _sendRequest(ClientConnection connection, Map<String, String> metadata) {
+    late final GrpcTransportStream stream;
     try {
-      _stream = connection.makeRequest(
+      stream = connection.makeRequest(
         _method.path,
         options.timeout,
         metadata,
@@ -287,16 +287,17 @@ class ClientCall<Q, R> implements Response {
           return _method.requestSerializer(data);
         })
         .handleError(_onRequestError)
-        .listen(_stream.outgoingMessages.add,
+        .listen(stream.outgoingMessages.add,
-            onError: _stream.outgoingMessages.addError,
+            onError: stream.outgoingMessages.addError,
-            onDone: _stream.outgoingMessages.close,
+            onDone: stream.outgoingMessages.close,
             cancelOnError: true);
+    _stream = stream;
     // The response stream might have been listened to before _stream was ready,
     // so try setting up the subscription here as well.
     _onResponseListen();
   }
 
-  void _finishTimelineWithError(GrpcError error, TimelineTask timeline) {
+  void _finishTimelineWithError(GrpcError error, TimelineTask? timeline) {
     timeline?.finish(arguments: {
       'error': error.toString(),
     });
@@ -315,28 +316,31 @@ class ClientCall<Q, R> implements Response {
     if (_stream != null &&
         _responses.hasListener &&
         _responseSubscription == null) {
-      _responseSubscription = _stream.incomingMessages.listen(_onResponseData,
+      // ignore: cancel_subscriptions
+      final subscription = _stream!.incomingMessages.listen(_onResponseData,
           onError: _onResponseError,
           onDone: _onResponseDone,
           cancelOnError: true);
       if (_responses.isPaused) {
-        _responseSubscription.pause();
+        subscription.pause();
       }
-      _responses.onPause = _responseSubscription.pause;
+      _responses.onPause = subscription.pause;
-      _responses.onResume = _responseSubscription.resume;
+      _responses.onResume = subscription.resume;
       _responses.onCancel = cancel;
+
+      _responseSubscription = subscription;
     }
   }
 
   /// Emit an error response to the user, and tear down this call.
-  void _responseError(GrpcError error, [StackTrace stackTrace]) {
+  void _responseError(GrpcError error, [StackTrace? stackTrace]) {
     _finishTimelineWithError(error, _responseTimeline);
     _responses.addError(error, stackTrace);
     _timeoutTimer?.cancel();
     _requestSubscription?.cancel();
-    _responseSubscription.cancel();
+    _responseSubscription!.cancel();
     _responses.close();
-    _stream.terminate();
+    _stream!.terminate();
   }
 
   /// If there's an error status then process it as a response error
@@ -345,15 +349,17 @@ class ClientCall<Q, R> implements Response {
     final statusCode = int.parse(status ?? '0');
 
     if (statusCode != 0) {
-      final message = metadata['grpc-message'] == null
+      final messageMetadata = metadata['grpc-message'];
-          ? null
+      final message =
-          : Uri.decodeFull(metadata['grpc-message']);
+          messageMetadata == null ? null : Uri.decodeFull(messageMetadata);
 
+      final statusDetails = metadata[_statusDetailsHeader];
       _responseError(GrpcError.custom(
-        statusCode,
+          statusCode,
-        message,
+          message,
-        decodeStatusDetails(metadata['grpc-status-details-bin']),
+          statusDetails == null
-      ));
+              ? const <GeneratedMessage>[]
+              : decodeStatusDetails(statusDetails)));
     }
   }
 
@@ -444,7 +450,7 @@ class ClientCall<Q, R> implements Response {
     _responseTimeline?.finish();
     _timeoutTimer?.cancel();
     _responses.close();
-    _responseSubscription.cancel();
+    _responseSubscription!.cancel();
   }
 
   /// Error handler for the requests stream. Something went wrong while trying
@@ -461,7 +467,7 @@ class ClientCall<Q, R> implements Response {
     _responses.close();
     _requestSubscription?.cancel();
     _responseSubscription?.cancel();
-    _stream.terminate();
+    _stream!.terminate();
   }
 
   Stream<R> get response => _responses.stream;
@@ -492,10 +498,10 @@ class ClientCall<Q, R> implements Response {
     _stream?.terminate();
     final futures = <Future>[];
     if (_requestSubscription != null) {
-      futures.add(_requestSubscription.cancel());
+      futures.add(_requestSubscription!.cancel());
     }
     if (_responseSubscription != null) {
-      futures.add(_responseSubscription.cancel());
+      futures.add(_responseSubscription!.cancel());
     }
     await Future.wait(futures);
   }

lib/src/client/channel.dart

@@ -44,8 +44,8 @@ abstract class ClientChannel {
 /// Auxiliary base class implementing much of ClientChannel.
 abstract class ClientChannelBase implements ClientChannel {
   // TODO(jakobr): Multiple connections, load balancing.
-  ClientConnection _connection;
+  late ClientConnection _connection;
-
+  var _connected = false;
   bool _isShutdown = false;
 
   ClientChannelBase();
@@ -54,13 +54,17 @@ abstract class ClientChannelBase implements ClientChannel {
   Future<void> shutdown() async {
     if (_isShutdown) return;
     _isShutdown = true;
-    if (_connection != null) await _connection.shutdown();
+    if (_connected) {
+      await _connection.shutdown();
+    }
   }
 
   @override
   Future<void> terminate() async {
     _isShutdown = true;
-    if (_connection != null) await _connection.terminate();
+    if (_connected) {
+      await _connection.terminate();
+    }
   }
 
   ClientConnection createConnection();
@@ -70,7 +74,11 @@ abstract class ClientChannelBase implements ClientChannel {
   /// The connection may be shared between multiple RPCs.
   Future<ClientConnection> getConnection() async {
     if (_isShutdown) throw GrpcError.unavailable('Channel shutting down.');
-    return _connection ??= createConnection();
+    if (!_connected) {
+      _connection = createConnection();
+      _connected = true;
+    }
+    return _connection;
   }
 
   @override

lib/src/client/client.dart

@@ -27,7 +27,7 @@ class Client {
 
   /// Interceptors will be applied in direct order before making a request.
   Client(this._channel,
-      {CallOptions options, Iterable<ClientInterceptor> interceptors})
+      {CallOptions? options, Iterable<ClientInterceptor>? interceptors})
       : _options = options ?? CallOptions(),
         _interceptors = List.unmodifiable(interceptors ?? Iterable.empty());
 
@@ -39,12 +39,12 @@ regenerate these stubs using  protobuf compiler plugin version 19.2.0 or newer.
 ''')
   ClientCall<Q, R> $createCall<Q, R>(
       ClientMethod<Q, R> method, Stream<Q> requests,
-      {CallOptions options}) {
+      {CallOptions? options}) {
     return _channel.createCall(method, requests, _options.mergedWith(options));
   }
 
   ResponseFuture<R> $createUnaryCall<Q, R>(ClientMethod<Q, R> method, Q request,
-      {CallOptions options}) {
+      {CallOptions? options}) {
     ClientUnaryInvoker<Q, R> invoker = (method, request, options) =>
         ResponseFuture<R>(
             _channel.createCall<Q, R>(method, Stream.value(request), options));
@@ -60,7 +60,7 @@ regenerate these stubs using  protobuf compiler plugin version 19.2.0 or newer.
 
   ResponseStream<R> $createStreamingCall<Q, R>(
       ClientMethod<Q, R> method, Stream<Q> requests,
-      {CallOptions options}) {
+      {CallOptions? options}) {
     ClientStreamingInvoker<Q, R> invoker = (method, request, options) =>
         ResponseStream<R>(_channel.createCall<Q, R>(method, requests, options));
 

lib/src/client/common.dart

@@ -46,21 +46,21 @@ class ResponseFuture<R> extends DelegatingFuture<R>
     with _ResponseMixin<dynamic, R> {
   final ClientCall<dynamic, R> _call;
 
-  static R _ensureOnlyOneResponse<R>(R previous, R element) {
+  static R _ensureOnlyOneResponse<R>(R? previous, R element) {
     if (previous != null) {
       throw GrpcError.unimplemented('More than one response received');
     }
     return element;
   }
 
-  static R _ensureOneResponse<R>(R value) {
+  static R _ensureOneResponse<R>(R? value) {
     if (value == null) throw GrpcError.unimplemented('No responses received');
     return value;
   }
 
   ResponseFuture(this._call)
       : super(_call.response
-            .fold(null, _ensureOnlyOneResponse)
+            .fold<R?>(null, _ensureOnlyOneResponse)
             .then(_ensureOneResponse));
 }
 

lib/src/client/connection.dart

@@ -42,9 +42,9 @@ abstract class ClientConnection {
   void dispatchCall(ClientCall call);
 
   /// Start a request for [path] with [metadata].
-  GrpcTransportStream makeRequest(String path, Duration timeout,
+  GrpcTransportStream makeRequest(String path, Duration? timeout,
       Map<String, String> metadata, ErrorHandler onRequestFailure,
-      {CallOptions callOptions});
+      {required CallOptions callOptions});
 
   /// Shuts down this connection.
   ///

lib/src/client/http2_connection.dart

@@ -44,19 +44,19 @@ class Http2ClientConnection implements connection.ClientConnection {
   connection.ConnectionState _state = ConnectionState.idle;
 
   @visibleForTesting
-  void Function(Http2ClientConnection connection) onStateChanged;
+  void Function(Http2ClientConnection connection)? onStateChanged;
   final _pendingCalls = <ClientCall>[];
 
   final ClientTransportConnector _transportConnector;
-  ClientTransportConnection _transportConnection;
+  ClientTransportConnection? _transportConnection;
 
   /// Used for idle and reconnect timeout, depending on [_state].
-  Timer _timer;
+  Timer? _timer;
 
   /// Used for making sure a single connection is not kept alive too long.
   final Stopwatch _connectionLifeTimer = Stopwatch();
 
-  Duration _currentReconnectDelay;
+  Duration? _currentReconnectDelay;
 
   Http2ClientConnection(Object host, int port, this.options)
       : _transportConnector = _SocketTransportConnector(host, port, options);
@@ -96,7 +96,7 @@ class Http2ClientConnection implements connection.ClientConnection {
       return;
     }
     _setState(ConnectionState.connecting);
-    connectTransport().then((transport) async {
+    connectTransport().then<void>((transport) async {
       _currentReconnectDelay = null;
       _transportConnection = transport;
       _connectionLifeTimer
@@ -119,11 +119,11 @@ class Http2ClientConnection implements connection.ClientConnection {
   ///
   /// Assumes [_transportConnection] is not `null`.
   void _refreshConnectionIfUnhealthy() {
-    final bool isHealthy = _transportConnection.isOpen;
+    final bool isHealthy = _transportConnection!.isOpen;
     final bool shouldRefresh =
         _connectionLifeTimer.elapsed > options.connectionTimeout;
     if (shouldRefresh) {
-      _transportConnection.finish();
+      _transportConnection!.finish();
     }
     if (!isHealthy || shouldRefresh) {
       _abandonConnection();
@@ -149,9 +149,9 @@ class Http2ClientConnection implements connection.ClientConnection {
     }
   }
 
-  GrpcTransportStream makeRequest(String path, Duration timeout,
+  GrpcTransportStream makeRequest(String path, Duration? timeout,
       Map<String, String> metadata, ErrorHandler onRequestFailure,
-      {CallOptions callOptions}) {
+      {CallOptions? callOptions}) {
     final compressionCodec = callOptions?.compression;
     final headers = createCallHeaders(
       credentials.isSecure,
@@ -165,7 +165,7 @@ class Http2ClientConnection implements connection.ClientConnection {
           (callOptions?.metadata ?? const {})['grpc-accept-encoding'] ??
               options.codecRegistry?.supportedEncodings,
     );
-    final stream = _transportConnection.makeRequest(headers);
+    final stream = _transportConnection!.makeRequest(headers);
     return Http2TransportStream(
       stream,
       onRequestFailure,
@@ -208,9 +208,7 @@ class Http2ClientConnection implements connection.ClientConnection {
 
   void _setState(ConnectionState state) {
     _state = state;
-    if (onStateChanged != null) {
+    onStateChanged?.call(this);
-      onStateChanged(this);
-    }
   }
 
   void _handleIdleTimeout() {
@@ -218,7 +216,7 @@ class Http2ClientConnection implements connection.ClientConnection {
     _cancelTimer();
     _transportConnection
         ?.finish()
-        ?.catchError((_) => {}); // TODO(jakobr): Log error.
+        .catchError((_) {}); // TODO(jakobr): Log error.
     _transportConnection = null;
     _setState(ConnectionState.idle);
   }
@@ -233,7 +231,7 @@ class Http2ClientConnection implements connection.ClientConnection {
       _cancelTimer();
     } else {
       if (options.idleTimeout != null) {
-        _timer ??= Timer(options.idleTimeout, _handleIdleTimeout);
+        _timer ??= Timer(options.idleTimeout!, _handleIdleTimeout);
       }
     }
   }
@@ -281,18 +279,18 @@ class Http2ClientConnection implements connection.ClientConnection {
     // We have pending RPCs. Reconnect after backoff delay.
     _setState(ConnectionState.transientFailure);
     _currentReconnectDelay = options.backoffStrategy(_currentReconnectDelay);
-    _timer = Timer(_currentReconnectDelay, _handleReconnect);
+    _timer = Timer(_currentReconnectDelay!, _handleReconnect);
   }
 
   static List<Header> createCallHeaders(
     bool useTls,
     String authority,
     String path,
-    Duration timeout,
+    Duration? timeout,
-    Map<String, String> metadata,
+    Map<String, String>? metadata,
-    Codec compressionCodec, {
+    Codec? compressionCodec, {
-    String userAgent,
+    String? userAgent,
-    String grpcAcceptEncodings,
+    String? grpcAcceptEncodings,
   }) {
     final headers = [
       _methodPost,
@@ -317,12 +315,14 @@ class Http2ClientConnection implements connection.ClientConnection {
 }
 
 class _SocketTransportConnector implements ClientTransportConnector {
+  /// Either [InternetAddress] or [String].
   final Object _host;
   final int _port;
   final ChannelOptions _options;
-  Socket _socket;
+  late Socket _socket; // ignore: close_sinks
 
-  _SocketTransportConnector(this._host, this._port, this._options);
+  _SocketTransportConnector(this._host, this._port, this._options)
+      : assert(_host is InternetAddress || _host is String);
 
   @override
   Future<ClientTransportConnection> connect() async {
@@ -349,19 +349,22 @@ class _SocketTransportConnector implements ClientTransportConnector {
   }
 
   @override
-  String get authority =>
+  String get authority {
-      _options.credentials.authority ??
+    final host =
-      (_port == 443 ? _host : "$_host:$_port");
+        _host is String ? _host as String : (_host as InternetAddress).host;
+    return _options.credentials.authority ??
+        (_port == 443 ? host : "$host:$_port");
+  }
 
   @override
   Future get done {
-    assert(_socket != null);
+    ArgumentError.checkNotNull(_socket);
     return _socket.done;
   }
 
   @override
   void shutdown() {
-    assert(_socket != null);
+    ArgumentError.checkNotNull(_socket);
     _socket.destroy();
   }
 

lib/src/client/interceptor.dart

@@ -3,10 +3,10 @@ import 'common.dart';
 import 'method.dart';
 
 typedef ClientUnaryInvoker<Q, R> = ResponseFuture<R> Function(
-    ClientMethod method, Q request, CallOptions options);
+    ClientMethod<Q, R> method, Q request, CallOptions options);
 
 typedef ClientStreamingInvoker<Q, R> = ResponseStream<R> Function(
-    ClientMethod method, Stream<Q> requests, CallOptions options);
+    ClientMethod<Q, R> method, Stream<Q> requests, CallOptions options);
 
 /// ClientInterceptors intercepts client calls before they are executed.
 ///

lib/src/client/options.dart

@@ -26,7 +26,7 @@ const defaultIdleTimeout = Duration(minutes: 5);
 const defaultConnectionTimeOut = Duration(minutes: 50);
 const defaultUserAgent = 'dart-grpc/2.0.0';
 
-typedef Duration BackoffStrategy(Duration lastBackoff);
+typedef Duration BackoffStrategy(Duration? lastBackoff);
 
 // Backoff algorithm from https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md
 const _initialBackoff = Duration(seconds: 1);
@@ -35,7 +35,7 @@ const _multiplier = 1.6;
 const _jitter = 0.2;
 final _random = Random();
 
-Duration defaultBackoffStrategy(Duration lastBackoff) {
+Duration defaultBackoffStrategy(Duration? lastBackoff) {
   if (lastBackoff == null) return _initialBackoff;
   final jitter = _random.nextDouble() * 2 * _jitter - _jitter;
   final nextBackoff = lastBackoff * (_multiplier + jitter);
@@ -45,8 +45,8 @@ Duration defaultBackoffStrategy(Duration lastBackoff) {
 /// Options controlling how connections are made on a [ClientChannel].
 class ChannelOptions {
   final ChannelCredentials credentials;
-  final Duration idleTimeout;
+  final Duration? idleTimeout;
-  final CodecRegistry codecRegistry;
+  final CodecRegistry? codecRegistry;
 
   /// The maximum time a single connection will be used for new requests.
   final Duration connectionTimeout;

lib/src/client/query_parameter.dart

@@ -29,17 +29,24 @@ class QueryParameter implements Comparable<QueryParameter> {
   String get value => values.first;
 
   /// Creates an instance by wrapping the single value in a [List].
-  QueryParameter(this.key, String value)
+  QueryParameter(this.key, String value) : values = [value] {
-      : assert(key != null && key.trim().isNotEmpty),
+    ArgumentError.checkNotNull(key);
-        values = [value];
+    if (key.trim().isEmpty) {
+      throw ArgumentError(key);
+    }
+  }
 
   /// Creates an instance from a [List] of values.
   ///
   /// This is not the default constructor since the single-value case is the
   /// most common.
   QueryParameter.multi(this.key, List<String> values)
-      : assert(key != null && key.trim().isNotEmpty),
+      : values = values..sort() {
-        values = values..sort();
+    ArgumentError.checkNotNull(key);
+    if (key.trim().isEmpty) {
+      throw ArgumentError(key);
+    }
+  }
 
   /// Returns the escaped value of the param as will appear in a URL.
   @override

lib/src/client/transport/http2_credentials.dart

@@ -32,32 +32,32 @@ bool allowBadCertificates(X509Certificate certificate, String host) => true;
 /// Options controlling TLS security settings on a [ClientChannel].
 class ChannelCredentials {
   final bool isSecure;
-  final String authority;
+  final String? authority;
-  final List<int> _certificateBytes;
+  final List<int>? _certificateBytes;
-  final String _certificatePassword;
+  final String? _certificatePassword;
-  final BadCertificateHandler onBadCertificate;
+  final BadCertificateHandler? onBadCertificate;
 
   const ChannelCredentials._(this.isSecure, this._certificateBytes,
       this._certificatePassword, this.authority, this.onBadCertificate);
 
   /// Disable TLS. RPCs are sent in clear text.
-  const ChannelCredentials.insecure({String authority})
+  const ChannelCredentials.insecure({String? authority})
       : this._(false, null, null, authority, null);
 
   /// Enable TLS and optionally specify the [certificates] to trust. If
   /// [certificates] is not provided, the default trust store is used.
   const ChannelCredentials.secure(
-      {List<int> certificates,
+      {List<int>? certificates,
-      String password,
+      String? password,
-      String authority,
+      String? authority,
-      BadCertificateHandler onBadCertificate})
+      BadCertificateHandler? onBadCertificate})
       : this._(true, certificates, password, authority, onBadCertificate);
 
-  SecurityContext get securityContext {
+  SecurityContext? get securityContext {
     if (!isSecure) return null;
     if (_certificateBytes != null) {
       return createSecurityContext(false)
-        ..setTrustedCertificatesBytes(_certificateBytes,
+        ..setTrustedCertificatesBytes(_certificateBytes!,
             password: _certificatePassword);
     }
     final context = new SecurityContext(withTrustedRoots: true);

lib/src/client/transport/http2_transport.dart

@@ -15,9 +15,10 @@
 
 import 'dart:async';
 
-import 'package:grpc/grpc.dart';
 import 'package:http2/transport.dart';
 
+import '../../shared/codec.dart';
+import '../../shared/codec_registry.dart';
 import '../../shared/message.dart';
 import '../../shared/streams.dart';
 import 'transport.dart';
@@ -33,8 +34,8 @@ class Http2TransportStream extends GrpcTransportStream {
   Http2TransportStream(
     this._transportStream,
     this._onError,
-    CodecRegistry codecRegistry,
+    CodecRegistry? codecRegistry,
-    Codec compression,
+    Codec? compression,
   ) : incomingMessages = _transportStream.incomingMessages
             .transform(GrpcHttpDecoder())
             .transform(grpcDecompressor(codecRegistry: codecRegistry)) {

lib/src/client/transport/web_streams.dart

@@ -47,10 +47,10 @@ class _GrpcWebConversionSink extends ChunkedConversionSink<ByteBuffer> {
   final _dataHeader = Uint8List(4);
 
   _GrpcWebParseState _state = _GrpcWebParseState.Init;
-  int _chunkOffset;
+  var _chunkOffset = 0;
-  int _frameType;
+  int? _frameType;
-  int _dataOffset = 0;
+  var _dataOffset = 0;
-  Uint8List _data;
+  Uint8List? _data;
 
   _GrpcWebConversionSink(this._out);
 
@@ -87,16 +87,16 @@ class _GrpcWebConversionSink extends ChunkedConversionSink<ByteBuffer> {
   }
 
   void _parseMessage(List<int> chunkData) {
-    final dataRemaining = _data.lengthInBytes - _dataOffset;
+    final dataRemaining = _data!.lengthInBytes - _dataOffset;
     if (dataRemaining > 0) {
       final chunkRemaining = chunkData.length - _chunkOffset;
       final toCopy = min(dataRemaining, chunkRemaining);
-      _data.setRange(
+      _data!
-          _dataOffset, _dataOffset + toCopy, chunkData, _chunkOffset);
+          .setRange(_dataOffset, _dataOffset + toCopy, chunkData, _chunkOffset);
       _dataOffset += toCopy;
       _chunkOffset += toCopy;
     }
-    if (_dataOffset == _data.lengthInBytes) {
+    if (_dataOffset == _data!.lengthInBytes) {
       _finishMessage();
     }
   }
@@ -104,10 +104,10 @@ class _GrpcWebConversionSink extends ChunkedConversionSink<ByteBuffer> {
   void _finishMessage() {
     switch (_frameType) {
       case frameTypeData:
-        _out.add(GrpcData(_data, isCompressed: false));
+        _out.add(GrpcData(_data!, isCompressed: false));
         break;
       case frameTypeTrailers:
-        final stringData = String.fromCharCodes(_data);
+        final stringData = String.fromCharCodes(_data!);
         final headers = _parseHttp1Headers(stringData);
         _out.add(GrpcMetadata(headers));
         break;
@@ -119,7 +119,7 @@ class _GrpcWebConversionSink extends ChunkedConversionSink<ByteBuffer> {
 
   Map<String, String> _parseHttp1Headers(String stringData) {
     final trimmed = stringData.trim();
-    final chunks = trimmed == '' ? [] : trimmed.split('\r\n');
+    final chunks = trimmed == '' ? <String>[] : trimmed.split('\r\n');
     final headers = <String, String>{};
     for (final chunk in chunks) {
       final pos = chunk.indexOf(':');

lib/src/client/transport/xhr_transport.dart

@@ -51,7 +51,8 @@ class XhrTransportStream implements GrpcTransportStream {
   @override
   StreamSink<List<int>> get outgoingMessages => _outgoingMessages.sink;
 
-  XhrTransportStream(this._request, {onError, onDone})
+  XhrTransportStream(this._request,
+      {required ErrorHandler onError, required onDone})
       : _onError = onError,
         _onDone = onDone {
     _outgoingMessages.stream
@@ -170,7 +171,7 @@ class XhrClientConnection extends ClientConnection {
 
   void _initializeRequest(HttpRequest request, Map<String, String> metadata) {
     for (final header in metadata.keys) {
-      request.setRequestHeader(header, metadata[header]);
+      request.setRequestHeader(header, metadata[header]!);
     }
     // Overriding the mimetype allows us to stream and parse the data
     request.overrideMimeType('text/plain; charset=x-user-defined');
@@ -181,9 +182,9 @@ class XhrClientConnection extends ClientConnection {
   HttpRequest createHttpRequest() => HttpRequest();
 
   @override
-  GrpcTransportStream makeRequest(String path, Duration timeout,
+  GrpcTransportStream makeRequest(String path, Duration? timeout,
       Map<String, String> metadata, ErrorHandler onError,
-      {CallOptions callOptions}) {
+      {CallOptions? callOptions}) {
     // gRPC-web headers.
     if (_getContentTypeHeader(metadata) == null) {
       metadata['Content-Type'] = 'application/grpc-web+proto';
@@ -231,7 +232,7 @@ class XhrClientConnection extends ClientConnection {
   Future<void> shutdown() async {}
 }
 
-MapEntry<String, String> _getContentTypeHeader(Map<String, String> metadata) {
+MapEntry<String, String>? _getContentTypeHeader(Map<String, String> metadata) {
   for (var entry in metadata.entries) {
     if (entry.key.toLowerCase() == _contentTypeKey.toLowerCase()) {
       return entry;

lib/src/generated/google/protobuf/any.pb.dart

@@ -2,7 +2,7 @@
 //  Generated code. Do not modify.
 //  source: google/protobuf/any.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
 import 'dart:core' as $core;
@@ -37,7 +37,19 @@ class Any extends $pb.GeneratedMessage with $mixin.AnyMixin {
     ..hasRequiredFields = false;
 
   Any._() : super();
-  factory Any() => create();
+  factory Any({
+    $core.String? typeUrl,
+    $core.List<$core.int>? value,
+  }) {
+    final _result = create();
+    if (typeUrl != null) {
+      _result.typeUrl = typeUrl;
+    }
+    if (value != null) {
+      _result.value = value;
+    }
+    return _result;
+  }
   factory Any.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -51,8 +63,9 @@ class Any extends $pb.GeneratedMessage with $mixin.AnyMixin {
   @$core.Deprecated('Using this can add significant overhead to your binary. '
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
-  Any copyWith(void Function(Any) updates) => super.copyWith(
+  Any copyWith(void Function(Any) updates) =>
-      (message) => updates(message as Any)); // ignore: deprecated_member_use
+      super.copyWith((message) => updates(message as Any))
+          as Any; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static Any create() => Any._();
@@ -61,7 +74,7 @@ class Any extends $pb.GeneratedMessage with $mixin.AnyMixin {
   @$core.pragma('dart2js:noInline')
   static Any getDefault() =>
       _defaultInstance ??= $pb.GeneratedMessage.$_defaultFor<Any>(create);
-  static Any _defaultInstance;
+  static Any? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get typeUrl => $_getSZ(0);

lib/src/generated/google/protobuf/any.pbenum.dart

@@ -2,5 +2,5 @@
 //  Generated code. Do not modify.
 //  source: google/protobuf/any.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields

lib/src/generated/google/protobuf/any.pbjson.dart

@@ -2,9 +2,11 @@
 //  Generated code. Do not modify.
 //  source: google/protobuf/any.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
+import 'dart:core' as $core;
+
 const Any$json = const {
   '1': 'Any',
   '2': const [

lib/src/generated/google/protobuf/duration.pb.dart

@@ -2,7 +2,7 @@
 //  Generated code. Do not modify.
 //  source: google/protobuf/duration.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
 import 'dart:core' as $core;
@@ -38,7 +38,19 @@ class Duration extends $pb.GeneratedMessage with $mixin.DurationMixin {
     ..hasRequiredFields = false;
 
   Duration._() : super();
-  factory Duration() => create();
+  factory Duration({
+    $fixnum.Int64? seconds,
+    $core.int? nanos,
+  }) {
+    final _result = create();
+    if (seconds != null) {
+      _result.seconds = seconds;
+    }
+    if (nanos != null) {
+      _result.nanos = nanos;
+    }
+    return _result;
+  }
   factory Duration.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -53,8 +65,8 @@ class Duration extends $pb.GeneratedMessage with $mixin.DurationMixin {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   Duration copyWith(void Function(Duration) updates) =>
-      super.copyWith((message) =>
+      super.copyWith((message) => updates(message as Duration))
-          updates(message as Duration)); // ignore: deprecated_member_use
+          as Duration; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static Duration create() => Duration._();
@@ -63,7 +75,7 @@ class Duration extends $pb.GeneratedMessage with $mixin.DurationMixin {
   @$core.pragma('dart2js:noInline')
   static Duration getDefault() =>
       _defaultInstance ??= $pb.GeneratedMessage.$_defaultFor<Duration>(create);
-  static Duration _defaultInstance;
+  static Duration? _defaultInstance;
 
   @$pb.TagNumber(1)
   $fixnum.Int64 get seconds => $_getI64(0);

lib/src/generated/google/protobuf/duration.pbenum.dart

@@ -2,5 +2,5 @@
 //  Generated code. Do not modify.
 //  source: google/protobuf/duration.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields

lib/src/generated/google/protobuf/duration.pbjson.dart

@@ -2,9 +2,11 @@
 //  Generated code. Do not modify.
 //  source: google/protobuf/duration.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
+import 'dart:core' as $core;
+
 const Duration$json = const {
   '1': 'Duration',
   '2': const [

lib/src/generated/google/rpc/code.pb.dart

@@ -2,7 +2,7 @@
 //  Generated code. Do not modify.
 //  source: google/rpc/code.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
 import 'dart:core' as $core;

lib/src/generated/google/rpc/code.pbenum.dart

@@ -2,7 +2,7 @@
 //  Generated code. Do not modify.
 //  source: google/rpc/code.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
 // ignore_for_file: UNDEFINED_SHOWN_NAME
@@ -115,7 +115,7 @@ class Code extends $pb.ProtobufEnum {
 
   static final $core.Map<$core.int, Code> _byValue =
       $pb.ProtobufEnum.initByValue(values);
-  static Code valueOf($core.int value) => _byValue[value];
+  static Code? valueOf($core.int value) => _byValue[value];
 
   const Code._($core.int v, $core.String n) : super(v, n);
 }

lib/src/generated/google/rpc/code.pbjson.dart

@@ -2,9 +2,11 @@
 //  Generated code. Do not modify.
 //  source: google/rpc/code.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
+import 'dart:core' as $core;
+
 const Code$json = const {
   '1': 'Code',
   '2': const [

lib/src/generated/google/rpc/error_details.pb.dart

@@ -2,7 +2,7 @@
 //  Generated code. Do not modify.
 //  source: google/rpc/error_details.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
 import 'dart:core' as $core;
@@ -30,7 +30,15 @@ class RetryInfo extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   RetryInfo._() : super();
-  factory RetryInfo() => create();
+  factory RetryInfo({
+    $1.Duration? retryDelay,
+  }) {
+    final _result = create();
+    if (retryDelay != null) {
+      _result.retryDelay = retryDelay;
+    }
+    return _result;
+  }
   factory RetryInfo.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -45,8 +53,8 @@ class RetryInfo extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   RetryInfo copyWith(void Function(RetryInfo) updates) =>
-      super.copyWith((message) =>
+      super.copyWith((message) => updates(message as RetryInfo))
-          updates(message as RetryInfo)); // ignore: deprecated_member_use
+          as RetryInfo; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static RetryInfo create() => RetryInfo._();
@@ -55,7 +63,7 @@ class RetryInfo extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static RetryInfo getDefault() =>
       _defaultInstance ??= $pb.GeneratedMessage.$_defaultFor<RetryInfo>(create);
-  static RetryInfo _defaultInstance;
+  static RetryInfo? _defaultInstance;
 
   @$pb.TagNumber(1)
   $1.Duration get retryDelay => $_getN(0);
@@ -95,7 +103,19 @@ class DebugInfo extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   DebugInfo._() : super();
-  factory DebugInfo() => create();
+  factory DebugInfo({
+    $core.Iterable<$core.String>? stackEntries,
+    $core.String? detail,
+  }) {
+    final _result = create();
+    if (stackEntries != null) {
+      _result.stackEntries.addAll(stackEntries);
+    }
+    if (detail != null) {
+      _result.detail = detail;
+    }
+    return _result;
+  }
   factory DebugInfo.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -110,8 +130,8 @@ class DebugInfo extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   DebugInfo copyWith(void Function(DebugInfo) updates) =>
-      super.copyWith((message) =>
+      super.copyWith((message) => updates(message as DebugInfo))
-          updates(message as DebugInfo)); // ignore: deprecated_member_use
+          as DebugInfo; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static DebugInfo create() => DebugInfo._();
@@ -120,7 +140,7 @@ class DebugInfo extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static DebugInfo getDefault() =>
       _defaultInstance ??= $pb.GeneratedMessage.$_defaultFor<DebugInfo>(create);
-  static DebugInfo _defaultInstance;
+  static DebugInfo? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.List<$core.String> get stackEntries => $_getList(0);
@@ -161,7 +181,19 @@ class QuotaFailure_Violation extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   QuotaFailure_Violation._() : super();
-  factory QuotaFailure_Violation() => create();
+  factory QuotaFailure_Violation({
+    $core.String? subject,
+    $core.String? description,
+  }) {
+    final _result = create();
+    if (subject != null) {
+      _result.subject = subject;
+    }
+    if (description != null) {
+      _result.description = description;
+    }
+    return _result;
+  }
   factory QuotaFailure_Violation.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -178,8 +210,8 @@ class QuotaFailure_Violation extends $pb.GeneratedMessage {
       'Will be removed in next major version')
   QuotaFailure_Violation copyWith(
           void Function(QuotaFailure_Violation) updates) =>
-      super.copyWith((message) => updates(
+      super.copyWith((message) => updates(message as QuotaFailure_Violation))
-          message as QuotaFailure_Violation)); // ignore: deprecated_member_use
+          as QuotaFailure_Violation; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static QuotaFailure_Violation create() => QuotaFailure_Violation._();
@@ -189,7 +221,7 @@ class QuotaFailure_Violation extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static QuotaFailure_Violation getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<QuotaFailure_Violation>(create);
-  static QuotaFailure_Violation _defaultInstance;
+  static QuotaFailure_Violation? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get subject => $_getSZ(0);
@@ -236,7 +268,15 @@ class QuotaFailure extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   QuotaFailure._() : super();
-  factory QuotaFailure() => create();
+  factory QuotaFailure({
+    $core.Iterable<QuotaFailure_Violation>? violations,
+  }) {
+    final _result = create();
+    if (violations != null) {
+      _result.violations.addAll(violations);
+    }
+    return _result;
+  }
   factory QuotaFailure.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -251,8 +291,8 @@ class QuotaFailure extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   QuotaFailure copyWith(void Function(QuotaFailure) updates) =>
-      super.copyWith((message) =>
+      super.copyWith((message) => updates(message as QuotaFailure))
-          updates(message as QuotaFailure)); // ignore: deprecated_member_use
+          as QuotaFailure; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static QuotaFailure create() => QuotaFailure._();
@@ -262,7 +302,7 @@ class QuotaFailure extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static QuotaFailure getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<QuotaFailure>(create);
-  static QuotaFailure _defaultInstance;
+  static QuotaFailure? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.List<QuotaFailure_Violation> get violations => $_getList(0);
@@ -300,7 +340,23 @@ class ErrorInfo extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   ErrorInfo._() : super();
-  factory ErrorInfo() => create();
+  factory ErrorInfo({
+    $core.String? reason,
+    $core.String? domain,
+    $core.Map<$core.String, $core.String>? metadata,
+  }) {
+    final _result = create();
+    if (reason != null) {
+      _result.reason = reason;
+    }
+    if (domain != null) {
+      _result.domain = domain;
+    }
+    if (metadata != null) {
+      _result.metadata.addAll(metadata);
+    }
+    return _result;
+  }
   factory ErrorInfo.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -315,8 +371,8 @@ class ErrorInfo extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   ErrorInfo copyWith(void Function(ErrorInfo) updates) =>
-      super.copyWith((message) =>
+      super.copyWith((message) => updates(message as ErrorInfo))
-          updates(message as ErrorInfo)); // ignore: deprecated_member_use
+          as ErrorInfo; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static ErrorInfo create() => ErrorInfo._();
@@ -325,7 +381,7 @@ class ErrorInfo extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static ErrorInfo getDefault() =>
       _defaultInstance ??= $pb.GeneratedMessage.$_defaultFor<ErrorInfo>(create);
-  static ErrorInfo _defaultInstance;
+  static ErrorInfo? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get reason => $_getSZ(0);
@@ -383,7 +439,23 @@ class PreconditionFailure_Violation extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   PreconditionFailure_Violation._() : super();
-  factory PreconditionFailure_Violation() => create();
+  factory PreconditionFailure_Violation({
+    $core.String? type,
+    $core.String? subject,
+    $core.String? description,
+  }) {
+    final _result = create();
+    if (type != null) {
+      _result.type = type;
+    }
+    if (subject != null) {
+      _result.subject = subject;
+    }
+    if (description != null) {
+      _result.description = description;
+    }
+    return _result;
+  }
   factory PreconditionFailure_Violation.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -400,8 +472,9 @@ class PreconditionFailure_Violation extends $pb.GeneratedMessage {
       'Will be removed in next major version')
   PreconditionFailure_Violation copyWith(
           void Function(PreconditionFailure_Violation) updates) =>
-      super.copyWith((message) => updates(message
+      super.copyWith(
-          as PreconditionFailure_Violation)); // ignore: deprecated_member_use
+              (message) => updates(message as PreconditionFailure_Violation))
+          as PreconditionFailure_Violation; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static PreconditionFailure_Violation create() =>
@@ -412,7 +485,7 @@ class PreconditionFailure_Violation extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static PreconditionFailure_Violation getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<PreconditionFailure_Violation>(create);
-  static PreconditionFailure_Violation _defaultInstance;
+  static PreconditionFailure_Violation? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get type => $_getSZ(0);
@@ -471,7 +544,15 @@ class PreconditionFailure extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   PreconditionFailure._() : super();
-  factory PreconditionFailure() => create();
+  factory PreconditionFailure({
+    $core.Iterable<PreconditionFailure_Violation>? violations,
+  }) {
+    final _result = create();
+    if (violations != null) {
+      _result.violations.addAll(violations);
+    }
+    return _result;
+  }
   factory PreconditionFailure.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -486,8 +567,8 @@ class PreconditionFailure extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   PreconditionFailure copyWith(void Function(PreconditionFailure) updates) =>
-      super.copyWith((message) => updates(
+      super.copyWith((message) => updates(message as PreconditionFailure))
-          message as PreconditionFailure)); // ignore: deprecated_member_use
+          as PreconditionFailure; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static PreconditionFailure create() => PreconditionFailure._();
@@ -497,7 +578,7 @@ class PreconditionFailure extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static PreconditionFailure getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<PreconditionFailure>(create);
-  static PreconditionFailure _defaultInstance;
+  static PreconditionFailure? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.List<PreconditionFailure_Violation> get violations => $_getList(0);
@@ -526,7 +607,19 @@ class BadRequest_FieldViolation extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   BadRequest_FieldViolation._() : super();
-  factory BadRequest_FieldViolation() => create();
+  factory BadRequest_FieldViolation({
+    $core.String? field_1,
+    $core.String? description,
+  }) {
+    final _result = create();
+    if (field_1 != null) {
+      _result.field_1 = field_1;
+    }
+    if (description != null) {
+      _result.description = description;
+    }
+    return _result;
+  }
   factory BadRequest_FieldViolation.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -543,8 +636,8 @@ class BadRequest_FieldViolation extends $pb.GeneratedMessage {
       'Will be removed in next major version')
   BadRequest_FieldViolation copyWith(
           void Function(BadRequest_FieldViolation) updates) =>
-      super.copyWith((message) => updates(message
+      super.copyWith((message) => updates(message as BadRequest_FieldViolation))
-          as BadRequest_FieldViolation)); // ignore: deprecated_member_use
+          as BadRequest_FieldViolation; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static BadRequest_FieldViolation create() => BadRequest_FieldViolation._();
@@ -554,7 +647,7 @@ class BadRequest_FieldViolation extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static BadRequest_FieldViolation getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<BadRequest_FieldViolation>(create);
-  static BadRequest_FieldViolation _defaultInstance;
+  static BadRequest_FieldViolation? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get field_1 => $_getSZ(0);
@@ -601,7 +694,15 @@ class BadRequest extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   BadRequest._() : super();
-  factory BadRequest() => create();
+  factory BadRequest({
+    $core.Iterable<BadRequest_FieldViolation>? fieldViolations,
+  }) {
+    final _result = create();
+    if (fieldViolations != null) {
+      _result.fieldViolations.addAll(fieldViolations);
+    }
+    return _result;
+  }
   factory BadRequest.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -616,8 +717,8 @@ class BadRequest extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   BadRequest copyWith(void Function(BadRequest) updates) =>
-      super.copyWith((message) =>
+      super.copyWith((message) => updates(message as BadRequest))
-          updates(message as BadRequest)); // ignore: deprecated_member_use
+          as BadRequest; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static BadRequest create() => BadRequest._();
@@ -626,7 +727,7 @@ class BadRequest extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static BadRequest getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<BadRequest>(create);
-  static BadRequest _defaultInstance;
+  static BadRequest? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.List<BadRequest_FieldViolation> get fieldViolations => $_getList(0);
@@ -655,7 +756,19 @@ class RequestInfo extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   RequestInfo._() : super();
-  factory RequestInfo() => create();
+  factory RequestInfo({
+    $core.String? requestId,
+    $core.String? servingData,
+  }) {
+    final _result = create();
+    if (requestId != null) {
+      _result.requestId = requestId;
+    }
+    if (servingData != null) {
+      _result.servingData = servingData;
+    }
+    return _result;
+  }
   factory RequestInfo.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -670,8 +783,8 @@ class RequestInfo extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   RequestInfo copyWith(void Function(RequestInfo) updates) =>
-      super.copyWith((message) =>
+      super.copyWith((message) => updates(message as RequestInfo))
-          updates(message as RequestInfo)); // ignore: deprecated_member_use
+          as RequestInfo; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static RequestInfo create() => RequestInfo._();
@@ -680,7 +793,7 @@ class RequestInfo extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static RequestInfo getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<RequestInfo>(create);
-  static RequestInfo _defaultInstance;
+  static RequestInfo? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get requestId => $_getSZ(0);
@@ -737,7 +850,27 @@ class ResourceInfo extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   ResourceInfo._() : super();
-  factory ResourceInfo() => create();
+  factory ResourceInfo({
+    $core.String? resourceType,
+    $core.String? resourceName,
+    $core.String? owner,
+    $core.String? description,
+  }) {
+    final _result = create();
+    if (resourceType != null) {
+      _result.resourceType = resourceType;
+    }
+    if (resourceName != null) {
+      _result.resourceName = resourceName;
+    }
+    if (owner != null) {
+      _result.owner = owner;
+    }
+    if (description != null) {
+      _result.description = description;
+    }
+    return _result;
+  }
   factory ResourceInfo.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -752,8 +885,8 @@ class ResourceInfo extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   ResourceInfo copyWith(void Function(ResourceInfo) updates) =>
-      super.copyWith((message) =>
+      super.copyWith((message) => updates(message as ResourceInfo))
-          updates(message as ResourceInfo)); // ignore: deprecated_member_use
+          as ResourceInfo; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static ResourceInfo create() => ResourceInfo._();
@@ -763,7 +896,7 @@ class ResourceInfo extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static ResourceInfo getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<ResourceInfo>(create);
-  static ResourceInfo _defaultInstance;
+  static ResourceInfo? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get resourceType => $_getSZ(0);
@@ -837,7 +970,19 @@ class Help_Link extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   Help_Link._() : super();
-  factory Help_Link() => create();
+  factory Help_Link({
+    $core.String? description,
+    $core.String? url,
+  }) {
+    final _result = create();
+    if (description != null) {
+      _result.description = description;
+    }
+    if (url != null) {
+      _result.url = url;
+    }
+    return _result;
+  }
   factory Help_Link.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -852,8 +997,8 @@ class Help_Link extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   Help_Link copyWith(void Function(Help_Link) updates) =>
-      super.copyWith((message) =>
+      super.copyWith((message) => updates(message as Help_Link))
-          updates(message as Help_Link)); // ignore: deprecated_member_use
+          as Help_Link; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static Help_Link create() => Help_Link._();
@@ -862,7 +1007,7 @@ class Help_Link extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static Help_Link getDefault() =>
       _defaultInstance ??= $pb.GeneratedMessage.$_defaultFor<Help_Link>(create);
-  static Help_Link _defaultInstance;
+  static Help_Link? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get description => $_getSZ(0);
@@ -909,7 +1054,15 @@ class Help extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   Help._() : super();
-  factory Help() => create();
+  factory Help({
+    $core.Iterable<Help_Link>? links,
+  }) {
+    final _result = create();
+    if (links != null) {
+      _result.links.addAll(links);
+    }
+    return _result;
+  }
   factory Help.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -923,8 +1076,9 @@ class Help extends $pb.GeneratedMessage {
   @$core.Deprecated('Using this can add significant overhead to your binary. '
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
-  Help copyWith(void Function(Help) updates) => super.copyWith(
+  Help copyWith(void Function(Help) updates) =>
-      (message) => updates(message as Help)); // ignore: deprecated_member_use
+      super.copyWith((message) => updates(message as Help))
+          as Help; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static Help create() => Help._();
@@ -933,7 +1087,7 @@ class Help extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static Help getDefault() =>
       _defaultInstance ??= $pb.GeneratedMessage.$_defaultFor<Help>(create);
-  static Help _defaultInstance;
+  static Help? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.List<Help_Link> get links => $_getList(0);
@@ -962,7 +1116,19 @@ class LocalizedMessage extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   LocalizedMessage._() : super();
-  factory LocalizedMessage() => create();
+  factory LocalizedMessage({
+    $core.String? locale,
+    $core.String? message,
+  }) {
+    final _result = create();
+    if (locale != null) {
+      _result.locale = locale;
+    }
+    if (message != null) {
+      _result.message = message;
+    }
+    return _result;
+  }
   factory LocalizedMessage.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -977,8 +1143,8 @@ class LocalizedMessage extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   LocalizedMessage copyWith(void Function(LocalizedMessage) updates) =>
-      super.copyWith((message) => updates(
+      super.copyWith((message) => updates(message as LocalizedMessage))
-          message as LocalizedMessage)); // ignore: deprecated_member_use
+          as LocalizedMessage; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static LocalizedMessage create() => LocalizedMessage._();
@@ -988,7 +1154,7 @@ class LocalizedMessage extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static LocalizedMessage getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<LocalizedMessage>(create);
-  static LocalizedMessage _defaultInstance;
+  static LocalizedMessage? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get locale => $_getSZ(0);

lib/src/generated/google/rpc/error_details.pbenum.dart

@@ -2,5 +2,5 @@
 //  Generated code. Do not modify.
 //  source: google/rpc/error_details.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields

lib/src/generated/google/rpc/error_details.pbjson.dart

@@ -2,9 +2,11 @@
 //  Generated code. Do not modify.
 //  source: google/rpc/error_details.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
+import 'dart:core' as $core;
+
 const RetryInfo$json = const {
   '1': 'RetryInfo',
   '2': const [

lib/src/generated/google/rpc/status.pb.dart

@@ -2,7 +2,7 @@
 //  Generated code. Do not modify.
 //  source: google/rpc/status.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
 import 'dart:core' as $core;
@@ -40,7 +40,23 @@ class Status extends $pb.GeneratedMessage {
         ..hasRequiredFields = false;
 
   Status._() : super();
-  factory Status() => create();
+  factory Status({
+    $core.int? code,
+    $core.String? message,
+    $core.Iterable<$0.Any>? details,
+  }) {
+    final _result = create();
+    if (code != null) {
+      _result.code = code;
+    }
+    if (message != null) {
+      _result.message = message;
+    }
+    if (details != null) {
+      _result.details.addAll(details);
+    }
+    return _result;
+  }
   factory Status.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -54,8 +70,9 @@ class Status extends $pb.GeneratedMessage {
   @$core.Deprecated('Using this can add significant overhead to your binary. '
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
-  Status copyWith(void Function(Status) updates) => super.copyWith(
+  Status copyWith(void Function(Status) updates) =>
-      (message) => updates(message as Status)); // ignore: deprecated_member_use
+      super.copyWith((message) => updates(message as Status))
+          as Status; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static Status create() => Status._();
@@ -64,7 +81,7 @@ class Status extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static Status getDefault() =>
       _defaultInstance ??= $pb.GeneratedMessage.$_defaultFor<Status>(create);
-  static Status _defaultInstance;
+  static Status? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.int get code => $_getIZ(0);

lib/src/generated/google/rpc/status.pbenum.dart

@@ -2,5 +2,5 @@
 //  Generated code. Do not modify.
 //  source: google/rpc/status.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields

lib/src/generated/google/rpc/status.pbjson.dart

@@ -2,9 +2,11 @@
 //  Generated code. Do not modify.
 //  source: google/rpc/status.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
+import 'dart:core' as $core;
+
 const Status$json = const {
   '1': 'Status',
   '2': const [

lib/src/server/call.dart

@@ -19,19 +19,19 @@
 /// ability to set custom metadata on the header/trailer sent to the client.
 abstract class ServiceCall {
   /// Custom metadata from the client.
-  Map<String, String> get clientMetadata;
+  Map<String, String>? get clientMetadata;
 
   /// Custom metadata to be sent to the client. Will be [null] once the headers
   /// have been sent, either when [sendHeaders] is called, or when the first
   /// response message is sent.
-  Map<String, String> get headers;
+  Map<String, String>? get headers;
 
   /// Custom metadata to be sent to the client after all response messages.
-  Map<String, String> get trailers;
+  Map<String, String>? get trailers;
 
   /// Deadline for this call. If the call is still active after this time, then
   /// the client or server may cancel it.
-  DateTime get deadline;
+  DateTime? get deadline;
 
   /// Returns [true] if the [deadline] has been exceeded.
   bool get isTimedOut;
@@ -50,5 +50,5 @@ abstract class ServiceCall {
   ///
   /// The call will be closed after calling this method, and no further
   /// responses can be sent.
-  void sendTrailers({int status, String message});
+  void sendTrailers({int? status, String? message});
 }

lib/src/server/handler.dart

@@ -31,32 +31,33 @@ import 'service.dart';
 /// Handles an incoming gRPC call.
 class ServerHandler_ extends ServiceCall {
   final ServerTransportStream _stream;
-  final Service Function(String service) _serviceLookup;
+  final Service? Function(String service) _serviceLookup;
   final List<Interceptor> _interceptors;
-  final CodecRegistry _codecRegistry;
+  final CodecRegistry? _codecRegistry;
 
-  StreamSubscription<GrpcMessage> _incomingSubscription;
+  // ignore: cancel_subscriptions
+  StreamSubscription<GrpcMessage>? _incomingSubscription;
 
-  Service _service;
+  late Service _service;
-  ServiceMethod _descriptor;
+  late ServiceMethod _descriptor;
 
-  Map<String, String> _clientMetadata;
+  Map<String, String>? _clientMetadata;
-  Codec _callEncodingCodec;
+  Codec? _callEncodingCodec;
 
-  StreamController _requests;
+  StreamController? _requests;
   bool _hasReceivedRequest = false;
 
-  Stream _responses;
+  late Stream _responses;
-  StreamSubscription _responseSubscription;
+  StreamSubscription? _responseSubscription;
   bool _headersSent = false;
 
-  Map<String, String> _customHeaders = {};
+  Map<String, String>? _customHeaders = {};
-  Map<String, String> _customTrailers = {};
+  Map<String, String>? _customTrailers = {};
 
-  DateTime _deadline;
+  DateTime? _deadline;
   bool _isCanceled = false;
   bool _isTimedOut = false;
-  Timer _timeoutTimer;
+  Timer? _timeoutTimer;
 
   ServerHandler_(
     this._serviceLookup,
@@ -65,17 +66,17 @@ class ServerHandler_ extends ServiceCall {
     this._codecRegistry,
   );
 
-  DateTime get deadline => _deadline;
+  DateTime? get deadline => _deadline;
 
   bool get isCanceled => _isCanceled;
 
   bool get isTimedOut => _isTimedOut;
 
-  Map<String, String> get clientMetadata => _clientMetadata;
+  Map<String, String>? get clientMetadata => _clientMetadata;
 
-  Map<String, String> get headers => _customHeaders;
+  Map<String, String>? get headers => _customHeaders;
 
-  Map<String, String> get trailers => _customTrailers;
+  Map<String, String>? get trailers => _customTrailers;
 
   void handle() {
     _stream.onTerminated = (_) => cancel();
@@ -95,23 +96,21 @@ class ServerHandler_ extends ServiceCall {
   /// We need the catchError() handler here, since otherwise the error would
   /// be an unhandled exception.
   void _cancelResponseSubscription() {
-    _responseSubscription?.cancel()?.catchError((_) {});
+    _responseSubscription?.cancel().catchError((_) {});
   }
 
   // -- Idle state, incoming data --
 
-  void _onDataIdle(GrpcMessage message) async {
+  void _onDataIdle(GrpcMessage headerMessage) async {
-    if (message is! GrpcMetadata) {
+    if (headerMessage is! GrpcMetadata) {
       _sendError(GrpcError.unimplemented('Expected header frame'));
       _sinkIncoming();
       return;
     }
-    _incomingSubscription.pause();
+    _incomingSubscription!.pause();
 
-    final headerMessage = message
-        as GrpcMetadata; // TODO(jakobr): Cast should not be necessary here.
     _clientMetadata = headerMessage.metadata;
-    final path = _clientMetadata[':path'];
+    final path = _clientMetadata![':path']!;
     final pathSegments = path.split('/');
     if (pathSegments.length < 3) {
       _sendError(GrpcError.unimplemented('Invalid path'));
@@ -122,19 +121,21 @@ class ServerHandler_ extends ServiceCall {
     final methodName = pathSegments[2];
     if (_codecRegistry != null) {
       final acceptedEncodings =
-          clientMetadata['grpc-accept-encoding']?.split(',') ?? [];
+          clientMetadata!['grpc-accept-encoding']?.split(',') ?? [];
       _callEncodingCodec = acceptedEncodings
-          .map(_codecRegistry.lookup)
+          .map(_codecRegistry!.lookup)
           .firstWhere((c) => c != null, orElse: () => null);
     }
 
-    _service = _serviceLookup(serviceName);
+    final service = _serviceLookup(serviceName);
-    _descriptor = _service?.$lookupMethod(methodName);
+    final descriptor = service?.$lookupMethod(methodName);
-    if (_descriptor == null) {
+    if (descriptor == null) {
       _sendError(GrpcError.unimplemented('Path $path not found'));
       _sinkIncoming();
       return;
     }
+    _service = service!;
+    _descriptor = descriptor;
 
     final error = await _applyInterceptors();
     if (error != null) {
@@ -146,7 +147,7 @@ class ServerHandler_ extends ServiceCall {
     _startStreamingRequest();
   }
 
-  GrpcError _onMetadata() {
+  GrpcError? _onMetadata() {
     try {
       _service.$onMetadata(this);
     } on GrpcError catch (error) {
@@ -158,7 +159,7 @@ class ServerHandler_ extends ServiceCall {
     return null;
   }
 
-  Future<GrpcError> _applyInterceptors() async {
+  Future<GrpcError?> _applyInterceptors() async {
     try {
       for (final interceptor in _interceptors) {
         final error = await interceptor(this, this._descriptor);
@@ -174,13 +175,14 @@ class ServerHandler_ extends ServiceCall {
   }
 
   void _startStreamingRequest() {
-    _requests = _descriptor.createRequestStream(_incomingSubscription);
+    final requests = _descriptor.createRequestStream(_incomingSubscription!);
-    _incomingSubscription.onData(_onDataActive);
+    _requests = requests;
+    _incomingSubscription!.onData(_onDataActive);
 
     final error = _onMetadata();
     if (error != null) {
-      if (!_requests.isClosed) {
+      if (!requests.isClosed) {
-        _requests
+        requests
           ..addError(error)
           ..close();
       }
@@ -190,16 +192,16 @@ class ServerHandler_ extends ServiceCall {
       return;
     }
 
-    _responses = _descriptor.handle(this, _requests.stream);
+    _responses = _descriptor.handle(this, requests.stream);
 
     _responseSubscription = _responses.listen(_onResponse,
         onError: _onResponseError,
         onDone: _onResponseDone,
         cancelOnError: true);
-    _incomingSubscription.onData(_onDataActive);
+    _incomingSubscription!.onData(_onDataActive);
-    _incomingSubscription.onDone(_onDoneExpected);
+    _incomingSubscription!.onDone(_onDoneExpected);
 
-    final timeout = fromTimeoutString(_clientMetadata['grpc-timeout']);
+    final timeout = fromTimeoutString(_clientMetadata!['grpc-timeout']);
     if (timeout != null) {
       _deadline = DateTime.now().add(timeout);
       _timeoutTimer = Timer(timeout, _onTimedOut);
@@ -212,8 +214,8 @@ class ServerHandler_ extends ServiceCall {
     _isCanceled = true;
     final error = GrpcError.deadlineExceeded('Deadline exceeded');
     _sendError(error);
-    if (!_requests.isClosed) {
+    if (!_requests!.isClosed) {
-      _requests
+      _requests!
         ..addError(error)
         ..close();
     }
@@ -225,7 +227,7 @@ class ServerHandler_ extends ServiceCall {
     if (message is! GrpcData) {
       final error = GrpcError.unimplemented('Expected request');
       _sendError(error);
-      _requests
+      _requests!
         ..addError(error)
         ..close();
       return;
@@ -234,14 +236,13 @@ class ServerHandler_ extends ServiceCall {
     if (_hasReceivedRequest && !_descriptor.streamingRequest) {
       final error = GrpcError.unimplemented('Too many requests');
       _sendError(error);
-      _requests
+      _requests!
         ..addError(error)
         ..close();
       return;
     }
 
-    // TODO(jakobr): Cast should not be necessary here.
+    final data = message;
-    final data = message as GrpcData;
     var request;
     try {
       request = _descriptor.deserialize(data.data);
@@ -249,12 +250,12 @@ class ServerHandler_ extends ServiceCall {
       final grpcError =
           GrpcError.internal('Error deserializing request: $error');
       _sendError(grpcError);
-      _requests
+      _requests!
         ..addError(grpcError)
         ..close();
       return;
     }
-    _requests.add(request);
+    _requests!.add(request);
     _hasReceivedRequest = true;
   }
 
@@ -269,9 +270,9 @@ class ServerHandler_ extends ServiceCall {
       _stream.sendData(frame(bytes, _callEncodingCodec));
     } catch (error) {
       final grpcError = GrpcError.internal('Error sending response: $error');
-      if (!_requests.isClosed) {
+      if (!_requests!.isClosed) {
         // If we can, alert the handler that things are going wrong.
-        _requests
+        _requests!
           ..addError(grpcError)
           ..close();
       }
@@ -295,17 +296,17 @@ class ServerHandler_ extends ServiceCall {
   void sendHeaders() {
     if (_headersSent) throw GrpcError.internal('Headers already sent');
 
-    _customHeaders..remove(':status')..remove('content-type');
+    _customHeaders!..remove(':status')..remove('content-type');
 
     // TODO(jakobr): Should come from package:http2?
     final outgoingHeadersMap = <String, String>{
       ':status': '200',
       'content-type': 'application/grpc',
       if (_callEncodingCodec != null)
-        'grpc-encoding': _callEncodingCodec.encodingName,
+        'grpc-encoding': _callEncodingCodec!.encodingName,
     };
 
-    outgoingHeadersMap.addAll(_customHeaders);
+    outgoingHeadersMap.addAll(_customHeaders!);
     _customHeaders = null;
 
     final outgoingHeaders = <Header>[];
@@ -315,7 +316,7 @@ class ServerHandler_ extends ServiceCall {
     _headersSent = true;
   }
 
-  void sendTrailers({int status = 0, String message}) {
+  void sendTrailers({int? status = 0, String? message}) {
     _timeoutTimer?.cancel();
 
     final outgoingTrailersMap = <String, String>{};
@@ -324,13 +325,13 @@ class ServerHandler_ extends ServiceCall {
       outgoingTrailersMap[':status'] = '200';
       outgoingTrailersMap['content-type'] = 'application/grpc';
 
-      _customHeaders..remove(':status')..remove('content-type');
+      _customHeaders!..remove(':status')..remove('content-type');
-      outgoingTrailersMap.addAll(_customHeaders);
+      outgoingTrailersMap.addAll(_customHeaders!);
       _customHeaders = null;
       _headersSent = true;
     }
-    _customTrailers..remove(':status')..remove('content-type');
+    _customTrailers!..remove(':status')..remove('content-type');
-    outgoingTrailersMap.addAll(_customTrailers);
+    outgoingTrailersMap.addAll(_customTrailers!);
     _customTrailers = null;
     outgoingTrailersMap['grpc-status'] = status.toString();
     if (message != null) {
@@ -354,11 +355,11 @@ class ServerHandler_ extends ServiceCall {
     // client, so we treat it as such.
     _timeoutTimer?.cancel();
     _isCanceled = true;
-    if (_requests != null && !_requests.isClosed) {
+    if (_requests != null && !_requests!.isClosed) {
-      _requests.addError(GrpcError.cancelled('Cancelled'));
+      _requests!.addError(GrpcError.cancelled('Cancelled'));
     }
     _cancelResponseSubscription();
-    _incomingSubscription.cancel();
+    _incomingSubscription!.cancel();
     _stream.terminate();
   }
 
@@ -371,20 +372,20 @@ class ServerHandler_ extends ServiceCall {
     if (!(_hasReceivedRequest || _descriptor.streamingRequest)) {
       final error = GrpcError.unimplemented('No request received');
       _sendError(error);
-      _requests.addError(error);
+      _requests!.addError(error);
     }
     _onDone();
   }
 
   void _onDone() {
     _requests?.close();
-    _incomingSubscription.cancel();
+    _incomingSubscription!.cancel();
   }
 
   /// Sink incoming requests. This is used when an error has already been
   /// reported, but we still need to consume the request stream from the client.
   void _sinkIncoming() {
-    _incomingSubscription
+    _incomingSubscription!
       ..onData((_) {})
       ..onDone(_onDone);
   }
@@ -405,6 +406,6 @@ class ServerHandler extends ServerHandler_ {
     Service Function(String service) serviceLookup,
     stream, [
     List<Interceptor> interceptors = const <Interceptor>[],
-    CodecRegistry codecRegistry,
+    CodecRegistry? codecRegistry,
   ]) : super(serviceLookup, stream, interceptors, codecRegistry);
 }

lib/src/server/interceptor.dart

@@ -10,5 +10,5 @@ import 'service.dart';
 /// If the interceptor returns a [GrpcError], the error will be returned as a response and [ServiceMethod] wouldn't be called.
 /// If the interceptor throws [Exception], [GrpcError.internal] with exception.toString() will be returned.
 /// If the interceptor returns null, the corresponding [ServiceMethod] of [Service] will be called.
-typedef Interceptor = FutureOr<GrpcError> Function(
+typedef Interceptor = FutureOr<GrpcError?> Function(
     ServiceCall call, ServiceMethod method);

lib/src/server/server.dart

@@ -16,10 +16,10 @@
 import 'dart:async';
 import 'dart:io';
 
-import 'package:grpc/grpc.dart';
 import 'package:http2/transport.dart';
 import 'package:meta/meta.dart';
 
+import '../shared/codec_registry.dart';
 import '../shared/security.dart';
 import 'handler.dart';
 import 'interceptor.dart';
@@ -33,7 +33,7 @@ abstract class ServerCredentials {
 
   /// Creates [SecurityContext] from these credentials if possible.
   /// Otherwise returns [null].
-  SecurityContext get securityContext;
+  SecurityContext? get securityContext;
 }
 
 /// Set of credentials that only allows local TCP connections.
@@ -42,14 +42,14 @@ class ServerLocalCredentials extends ServerCredentials {
   bool validateClient(Socket socket) => socket.remoteAddress.isLoopback;
 
   @override
-  SecurityContext get securityContext => null;
+  SecurityContext? get securityContext => null;
 }
 
 class ServerTlsCredentials extends ServerCredentials {
-  final List<int> certificate;
+  final List<int>? certificate;
-  final String certificatePassword;
+  final String? certificatePassword;
-  final List<int> privateKey;
+  final List<int>? privateKey;
-  final String privateKeyPassword;
+  final String? privateKeyPassword;
 
   /// TLS credentials for a [Server].
   ///
@@ -64,10 +64,10 @@ class ServerTlsCredentials extends ServerCredentials {
   SecurityContext get securityContext {
     final context = createSecurityContext(true);
     if (privateKey != null) {
-      context.usePrivateKeyBytes(privateKey, password: privateKeyPassword);
+      context.usePrivateKeyBytes(privateKey!, password: privateKeyPassword);
     }
     if (certificate != null) {
-      context.useCertificateChainBytes(certificate,
+      context.useCertificateChainBytes(certificate!,
           password: certificatePassword);
     }
     return context;
@@ -84,7 +84,7 @@ class ServerTlsCredentials extends ServerCredentials {
 class ConnectionServer {
   final Map<String, Service> _services = {};
   final List<Interceptor> _interceptors;
-  final CodecRegistry _codecRegistry;
+  final CodecRegistry? _codecRegistry;
 
   final _connections = <ServerTransportConnection>[];
 
@@ -92,7 +92,7 @@ class ConnectionServer {
   ConnectionServer(
     List<Service> services, [
     List<Interceptor> interceptors = const <Interceptor>[],
-    CodecRegistry codecRegistry,
+    CodecRegistry? codecRegistry,
   ])  : _codecRegistry = codecRegistry,
         _interceptors = interceptors {
     for (final service in services) {
@@ -100,11 +100,11 @@ class ConnectionServer {
     }
   }
 
-  Service lookupService(String service) => _services[service];
+  Service? lookupService(String service) => _services[service];
 
   Future<void> serveConnection(ServerTransportConnection connection) async {
     _connections.add(connection);
-    ServerHandler_ handler;
+    ServerHandler_? handler;
     // TODO(jakobr): Set active state handlers, close connection after idle
     // timeout.
     connection.incomingStreams.listen((stream) {
@@ -134,39 +134,39 @@ class ConnectionServer {
 ///
 /// Listens for incoming RPCs, dispatching them to the right [Service] handler.
 class Server extends ConnectionServer {
-  ServerSocket _insecureServer;
+  ServerSocket? _insecureServer;
-  SecureServerSocket _secureServer;
+  SecureServerSocket? _secureServer;
 
   /// Create a server for the given [services].
   Server(
     List<Service> services, [
     List<Interceptor> interceptors = const <Interceptor>[],
-    CodecRegistry codecRegistry,
+    CodecRegistry? codecRegistry,
   ]) : super(services, interceptors, codecRegistry);
 
   /// The port that the server is listening on, or `null` if the server is not
   /// active.
-  int get port {
+  int? get port {
-    if (_secureServer != null) return _secureServer.port;
+    if (_secureServer != null) return _secureServer!.port;
-    if (_insecureServer != null) return _insecureServer.port;
+    if (_insecureServer != null) return _insecureServer!.port;
     return null;
   }
 
-  Service lookupService(String service) => _services[service];
+  Service? lookupService(String service) => _services[service];
 
   /// Starts the [Server] with the given options.
   /// [address] can be either a [String] or an [InternetAddress], in the latter
   /// case it can be a Unix Domain Socket address.
   Future<void> serve(
       {dynamic address,
-      int port,
+      int? port,
-      ServerCredentials security,
+      ServerCredentials? security,
-      ServerSettings http2ServerSettings,
+      ServerSettings? http2ServerSettings,
       int backlog: 0,
       bool v6Only: false,
       bool shared: false}) async {
     // TODO(dart-lang/grpc-dart#9): Handle HTTP/1.1 upgrade to h2c, if allowed.
-    Stream<Socket> server;
+    Stream<Socket>? server;
     final securityContext = security?.securityContext;
     if (securityContext != null) {
       _secureServer = await SecureServerSocket.bind(
@@ -183,7 +183,7 @@ class Server extends ConnectionServer {
       );
       server = _insecureServer;
     }
-    server.listen((socket) {
+    server!.listen((socket) {
       // Don't wait for io buffers to fill up before sending requests.
       if (socket.address.type != InternetAddressType.unix) {
         socket.setOption(SocketOption.tcpNoDelay, true);
@@ -213,10 +213,10 @@ class Server extends ConnectionServer {
   Future<void> shutdown() async {
     final done = _connections.map((connection) => connection.finish()).toList();
     if (_insecureServer != null) {
-      done.add(_insecureServer.close());
+      done.add(_insecureServer!.close());
     }
     if (_secureServer != null) {
-      done.add(_secureServer.close());
+      done.add(_secureServer!.close());
     }
     await Future.wait(done);
     _insecureServer = null;

lib/src/server/service.dart

@@ -56,36 +56,39 @@ class ServiceMethod<Q, R> {
         return handler(call, _toSingleFuture(requests));
       }
     } else {
-      Future<R> response;
+      final response = streamingRequest
-      if (streamingRequest) {
+          ? handler(call, requests)
-        response = handler(call, requests);
+          : handler(call, _toSingleFuture(requests));
-      } else {
-        response = handler(call, _toSingleFuture(requests));
-      }
       return response.asStream();
     }
   }
 
   Future<Q> _toSingleFuture(Stream<Q> stream) {
-    Q _ensureOnlyOneRequest(Q previous, Q element) {
+    Q _ensureOnlyOneRequest(Q? previous, Q element) {
       if (previous != null) {
         throw GrpcError.unimplemented('More than one request received');
       }
       return element;
     }
 
-    Q _ensureOneRequest(Q value) {
+    Q _ensureOneRequest(Q? value) {
       if (value == null) throw GrpcError.unimplemented('No requests received');
       return value;
     }
 
     final future =
-        stream.fold(null, _ensureOnlyOneRequest).then(_ensureOneRequest);
+        stream.fold<Q?>(null, _ensureOnlyOneRequest).then(_ensureOneRequest);
     // Make sure errors on the future aren't unhandled, but return the original
     // future so the request handler can also get the error.
-    future.catchError((_) {});
+    _awaitAndCatch(future);
     return future;
   }
+
+  void _awaitAndCatch<Q>(Future<Q> f) async {
+    try {
+      await f;
+    } catch (_) {}
+  }
 }
 
 /// Definition of a gRPC service.
@@ -104,5 +107,5 @@ abstract class Service {
   /// metadata from the client.
   void $onMetadata(ServiceCall context) {}
 
-  ServiceMethod $lookupMethod(String name) => _$methods[name];
+  ServiceMethod? $lookupMethod(String name) => _$methods[name];
 }

lib/src/shared/codec.dart

@@ -36,7 +36,7 @@ class IdentityCodec implements Codec {
   const IdentityCodec();
 
   @override
-  String get encodingName => "identity";
+  final encodingName = 'identity';
 
   @override
   List<int> compress(List<int> data) {
@@ -54,11 +54,11 @@ class GzipCodec implements Codec {
   const GzipCodec();
 
   @override
-  String get encodingName => "gzip";
+  final encodingName = "gzip";
 
   @override
   List<int> compress(List<int> data) {
-    return GZipEncoder().encode(data);
+    return GZipEncoder().encode(data)!;
   }
 
   @override

lib/src/shared/codec_registry.dart

@@ -18,8 +18,7 @@ import 'codec.dart';
 /// Encloses classes related to the compression and decompression of messages.
 class CodecRegistry {
   CodecRegistry({List<Codec> codecs = const [IdentityCodec()]})
-      : assert(codecs != null),
+      : _codecs = {for (var codec in codecs) codec.encodingName: codec},
-        _codecs = Map.fromIterable(codecs, key: (c) => c.encodingName),
         _supportedEncodings = codecs.map((c) {
           if (c.encodingName.contains(',')) {
             throw ArgumentError.value(c.encodingName, 'codecs',
@@ -33,16 +32,14 @@ class CodecRegistry {
     }
   }
 
-  factory CodecRegistry.empty() {
+  factory CodecRegistry.empty() => CodecRegistry(codecs: []);
-    return CodecRegistry(codecs: []);
-  }
 
   /// Key refers to the `encodingName` param from the [Codec].
   final Map<String, Codec> _codecs;
 
   final String _supportedEncodings;
 
-  Codec lookup(String codecName) {
+  Codec? lookup(String codecName) {
     return _codecs[codecName];
   }
 

lib/src/shared/message.dart

@@ -33,32 +33,36 @@ class GrpcMetadata extends GrpcMessage {
 class GrpcData extends GrpcMessage {
   final List<int> data;
   final bool isCompressed;
-  GrpcData(this.data, {this.isCompressed}) : assert(data != null);
+  GrpcData(this.data, {required this.isCompressed}) {
+    ArgumentError.checkNotNull(data);
+  }
 
   @override
   String toString() => 'gRPC Data (${data.length} bytes)';
 }
 
 class GrpcMessageSink extends Sink<GrpcMessage> {
-  GrpcMessage message;
+  late final GrpcMessage message;
+  bool _messageReceived = false;
 
   @override
   void add(GrpcMessage data) {
-    if (message != null) {
+    if (_messageReceived) {
       throw StateError('Too many messages received!');
     }
     message = data;
+    _messageReceived = true;
   }
 
   @override
   void close() {
-    if (message == null) {
+    if (!_messageReceived) {
       throw StateError('No messages received!');
     }
   }
 }
 
-List<int> frame(List<int> rawPayload, [Codec codec]) {
+List<int> frame(List<int> rawPayload, [Codec? codec]) {
   final compressedPayload =
       codec == null ? rawPayload : codec.compress(rawPayload);
   final payloadLength = compressedPayload.length;
@@ -71,9 +75,9 @@ List<int> frame(List<int> rawPayload, [Codec codec]) {
 }
 
 StreamTransformer<GrpcMessage, GrpcMessage> grpcDecompressor({
-  CodecRegistry codecRegistry,
+  CodecRegistry? codecRegistry,
 }) {
-  Codec codec;
+  Codec? codec;
   return StreamTransformer<GrpcMessage, GrpcMessage>.fromHandlers(
       handleData: (GrpcMessage value, EventSink<GrpcMessage> sink) {
     if (value is GrpcData && value.isCompressed) {
@@ -83,12 +87,12 @@ StreamTransformer<GrpcMessage, GrpcMessage> grpcDecompressor({
         );
         return;
       }
-      sink.add(GrpcData(codec.decompress(value.data), isCompressed: false));
+      sink.add(GrpcData(codec!.decompress(value.data), isCompressed: false));
       return;
     }
 
     if (value is GrpcMetadata && value.metadata.containsKey('grpc-encoding')) {
-      codec = codecRegistry?.lookup(value.metadata['grpc-encoding']);
+      codec = codecRegistry?.lookup(value.metadata['grpc-encoding']!);
     }
     sink.add(value);
   });

lib/src/shared/profiler.dart

@@ -16,12 +16,12 @@
 import 'dart:developer';
 
 typedef TimelineTask TimelineTaskFactory(
-    {String filterKey, TimelineTask parent});
+    {String? filterKey, TimelineTask? parent});
 
 TimelineTaskFactory timelineTaskFactory = _defaultTimelineTaskFactory;
 
 TimelineTask _defaultTimelineTaskFactory(
-        {String filterKey, TimelineTask parent}) =>
+        {String? filterKey, TimelineTask? parent}) =>
     TimelineTask(filterKey: filterKey, parent: parent);
 
 const String clientTimelineFilterKey = 'grpc/client';

lib/src/shared/status.dart

@@ -125,9 +125,9 @@ class StatusCode {
 class GrpcError implements Exception {
   final int code;
   final String codeName;
-  final String message;
+  final String? message;
-  final List<GeneratedMessage> details;
+  final Object? rawResponse;
-  final Object rawResponse;
+  final List<GeneratedMessage>? details;
 
   /// Custom error code.
   GrpcError.custom(this.code, [this.message, this.details, this.rawResponse])

lib/src/shared/streams.dart

@@ -58,7 +58,7 @@ class _GrpcMessageConversionSink extends ChunkedConversionSink<StreamMessage> {
   final Sink<GrpcMessage> _out;
 
   final _dataHeader = Uint8List(5);
-  Uint8List _data;
+  Uint8List? _data;
   int _dataOffset = 0;
 
   _GrpcMessageConversionSink(this._out);
@@ -87,17 +87,17 @@ class _GrpcMessageConversionSink extends ChunkedConversionSink<StreamMessage> {
       }
       if (_data != null) {
         // Reading data.
-        final dataRemaining = _data.lengthInBytes - _dataOffset;
+        final dataRemaining = _data!.lengthInBytes - _dataOffset;
         if (dataRemaining > 0) {
           final chunkRemaining = chunkLength - chunkReadOffset;
           final toCopy = min(dataRemaining, chunkRemaining);
-          _data.setRange(
+          _data!.setRange(
               _dataOffset, _dataOffset + toCopy, chunkData, chunkReadOffset);
           _dataOffset += toCopy;
           chunkReadOffset += toCopy;
         }
-        if (_dataOffset == _data.lengthInBytes) {
+        if (_dataOffset == _data!.lengthInBytes) {
-          _out.add(GrpcData(_data,
+          _out.add(GrpcData(_data!,
               isCompressed: _dataHeader.buffer.asByteData().getUint8(0) != 0));
           _data = null;
           _dataOffset = 0;

lib/src/shared/timeout.dart

@@ -17,7 +17,6 @@
 // Mostly inspired by grpc-java implementation.
 // TODO(jakobr): Modify to match grpc/core implementation instead.
 String toTimeoutString(Duration duration) {
-  if (duration == null) return null;
   const cutoff = 100000;
   final timeout = duration.inMicroseconds;
   if (timeout < 0) {
@@ -38,7 +37,7 @@ String toTimeoutString(Duration duration) {
 
 /// Convert [timeout] from grpc-timeout header string format to [Duration].
 /// Returns [null] if [timeout] is not correctly formatted.
-Duration fromTimeoutString(String timeout) {
+Duration? fromTimeoutString(String? timeout) {
   if (timeout == null) return null;
   if (timeout.length < 2) return null;
   final value = int.tryParse(timeout.substring(0, timeout.length - 1));

pubspec.yaml

@@ -1,28 +1,42 @@
 name: grpc
 description: Dart implementation of gRPC, a high performance, open-source universal RPC framework.
 
-version: 2.9.0
+version: 3.0.0-nullsafety.0
 
 homepage: https://github.com/dart-lang/grpc-dart
 
 environment:
-  sdk: '>=2.8.0 <3.0.0'
+  sdk: '>=2.12.0-0 <3.0.0'
 
 dependencies:
-  archive: ^2.0.13
+  archive: ^3.0.0-nullsafety
   async: ^2.2.0
-  crypto: ^2.1.4
+  crypto: ^3.0.0-nullsafety
-  fixnum: ^0.10.11
+  fixnum: ^1.0.0-nullsafety
   googleapis_auth: ^0.2.7
   meta: ^1.1.6
   http: ^0.12.0
-  http2: ^1.0.0
+  http2: ^2.0.0-nullsafety
-  protobuf: ^1.0.1
+  protobuf: ^2.0.0-nullsafety.1
 
 dev_dependencies:
-  build_runner: ^1.5.2
+  build_runner: ^1.11.0
-  build_test: ^0.10.8
+  build_test: ^1.3.4
-  build_web_compilers: ^2.1.1
+  mockito: ^5.0.0-nullsafety.5
-  mockito: ^4.1.0
+  test: ^1.16.0-nullsafety.16
-  test: ^1.6.4
   stream_channel: ^2.0.0
+  stream_transform: ^2.0.0-nullsafety
+
+dependency_overrides:
+  http:
+    git:
+      url: https://github.com/dart-lang/http.git
+      ref: 3845753a54624b070828cb3eff7a6c2a4e046cfb
+  googleapis_auth:
+    git:
+      url: https://github.com/dart-lang/googleapis_auth.git
+      ref: 30c084b7650fbd3e52525a127e0e65fc528e85a8
+  shelf:
+    git:
+      url: https://github.com/dart-lang/shelf.git
+      ref: 2102572a6c27b1321823bb3e3723ddb5448e04ae

test/client_handles_bad_connections_test.dart

@@ -16,7 +16,7 @@ class TestClient extends grpc.Client {
       (List<int> value) => value[0]);
 
   TestClient(ClientChannel channel) : super(channel);
-  grpc.ResponseStream<int> stream(int request, {grpc.CallOptions options}) {
+  grpc.ResponseStream<int> stream(int request, {grpc.CallOptions? options}) {
     return $createStreamingCall(_$stream, Stream.value(request),
         options: options);
   }
@@ -56,7 +56,7 @@ main() async {
 
     final channel = FixedConnectionClientChannel(Http2ClientConnection(
       address,
-      server.port,
+      server.port!,
       grpc.ChannelOptions(
         idleTimeout: Duration(minutes: 1),
         // Short delay to test that it will time out.
@@ -84,7 +84,7 @@ main() async {
 
     final channel = FixedConnectionClientChannel(Http2ClientConnection(
         address,
-        server.port,
+        server.port!,
         grpc.ChannelOptions(credentials: grpc.ChannelCredentials.insecure())));
     final states = <grpc.ConnectionState>[];
     channel.clientConnection.onStateChanged =

test/client_tests/client_test.dart

@@ -31,7 +31,7 @@ import '../src/utils.dart';
 void main() {
   const dummyValue = 0;
 
-  ClientHarness harness;
+  late ClientHarness harness;
 
   setUp(() {
     harness = ClientHarness()..setUp();
@@ -399,8 +399,8 @@ void main() {
 
   test('Connection errors are reported', () async {
     final connectionStates = <ConnectionState>[];
-    harness.connection.connectionError = 'Connection error';
+    harness.connection!.connectionError = 'Connection error';
-    harness.connection.onStateChanged = (connection) {
+    harness.connection!.onStateChanged = (connection) {
       final state = connection.state;
       connectionStates.add(state);
     };
@@ -418,7 +418,7 @@ void main() {
   test('Connections time out if idle', () async {
     final done = Completer();
     final connectionStates = <ConnectionState>[];
-    harness.connection.onStateChanged = (connection) {
+    harness.connection!.onStateChanged = (connection) {
       final state = connection.state;
       connectionStates.add(state);
       if (state == ConnectionState.idle) done.complete();
@@ -464,7 +464,7 @@ void main() {
         credentials: ChannelCredentials.insecure(authority: 'myauthority.com'));
     expect(Http2ClientConnection('localhost', 8080, channelOptions).authority,
         'myauthority.com');
-    expect(Http2ClientConnection('localhost', null, channelOptions).authority,
+    expect(Http2ClientConnection('localhost', 443, channelOptions).authority,
         'myauthority.com');
   });
 
@@ -485,12 +485,6 @@ void main() {
     expect(decodedDetails.length, 0);
   });
 
-  test('decodeStatusDetails should handle a null input', () {
-    final decodedDetails = decodeStatusDetails(null);
-    expect(decodedDetails, isA<List<GeneratedMessage>>());
-    expect(decodedDetails.length, 0);
-  });
-
   test('parseGeneratedMessage should parse out a valid Any type', () {
     final status = Status.fromBuffer(base64Url.decode(
         'CAMSEGFtb3VudCB0b28gc21hbGwafgopdHlwZS5nb29nbGVhcGlzLmNvbS9nb29nbGUucnBjLkJhZFJlcXVlc3QSUQpPCgZhbW91bnQSRVRoZSByZXF1aXJlZCBjdXJyZW5jeSBjb252ZXJzaW9uIHdvdWxkIHJlc3VsdCBpbiBhIHplcm8gdmFsdWUgcGF5bWVudA=='));

test/client_tests/client_transport_connector_test.dart

@@ -26,7 +26,7 @@ import '../src/utils.dart';
 void main() {
   const dummyValue = 0;
 
-  ClientTransportConnectorHarness harness;
+  late ClientTransportConnectorHarness harness;
 
   setUp(() {
     harness = ClientTransportConnectorHarness()..setUp();
@@ -349,8 +349,8 @@ void main() {
 
   test('Connection errors are reported', () async {
     final connectionStates = <ConnectionState>[];
-    harness.connection.connectionError = 'Connection error';
+    harness.connection!.connectionError = 'Connection error';
-    harness.connection.onStateChanged = (connection) {
+    harness.connection!.onStateChanged = (connection) {
       final state = connection.state;
       connectionStates.add(state);
     };
@@ -368,7 +368,7 @@ void main() {
   test('Connections time out if idle', () async {
     final done = Completer();
     final connectionStates = <ConnectionState>[];
-    harness.connection.onStateChanged = (connection) {
+    harness.connection!.onStateChanged = (connection) {
       final state = connection.state;
       connectionStates.add(state);
       if (state == ConnectionState.idle) done.complete();
@@ -414,7 +414,7 @@ void main() {
         credentials: ChannelCredentials.insecure(authority: 'myauthority.com'));
     expect(Http2ClientConnection('localhost', 8080, channelOptions).authority,
         'myauthority.com');
-    expect(Http2ClientConnection('localhost', null, channelOptions).authority,
+    expect(Http2ClientConnection('localhost', 443, channelOptions).authority,
         'myauthority.com');
   });
 }

test/client_tests/client_xhr_transport_test.dart

@@ -18,16 +18,22 @@ import 'dart:async';
 
 import 'dart:html';
 
+import 'package:async/async.dart';
 import 'package:grpc/src/client/call.dart';
 import 'package:grpc/src/client/transport/xhr_transport.dart';
 import 'package:grpc/src/shared/message.dart';
 import 'package:grpc/src/shared/status.dart';
 import 'package:mockito/mockito.dart';
+import 'package:stream_transform/stream_transform.dart';
 
 import 'package:test/test.dart';
 
+final readyStateChangeEvent =
+    Event('readystatechange', canBubble: false, cancelable: false);
+final progressEvent = ProgressEvent('onloadstart');
+
 class MockHttpRequest extends Mock implements HttpRequest {
-  MockHttpRequest({int code}) : status = code ?? 200;
+  MockHttpRequest({int? code}) : status = code ?? 200;
   // ignore: close_sinks
   StreamController<Event> readyStateChangeController =
       StreamController<Event>();
@@ -46,14 +52,20 @@ class MockHttpRequest extends Mock implements HttpRequest {
 
   @override
   final int status;
+
+  int get readyState => super.noSuchMethod(Invocation.getter(#readyState), -1);
+
+  @override
+  Map<String, String> get responseHeaders => super
+      .noSuchMethod(Invocation.getter(#responseHeaders), <String, String>{});
 }
 
 class MockXhrClientConnection extends XhrClientConnection {
-  MockXhrClientConnection({int code})
+  MockXhrClientConnection({int? code})
       : _statusCode = code ?? 200,
         super(Uri.parse('test:8080'));
 
-  MockHttpRequest latestRequest;
+  late MockHttpRequest latestRequest;
   final int _statusCode;
 
   @override
@@ -199,28 +211,40 @@ void main() {
   });
 
   test('Stream handles headers properly', () async {
-    final metadata = <String, String>{
+    final responseHeaders = {
       'parameter_1': 'value_1',
       'parameter_2': 'value_2'
     };
 
     final transport = MockXhrClientConnection();
 
-    final stream = transport.makeRequest('test_path', Duration(seconds: 10),
+    final stream = transport.makeRequest('test_path', Duration(seconds: 10), {},
-        metadata, (error, _) => fail(error.toString()));
+        (error, _) => fail(error.toString()));
 
-    stream.incomingMessages.listen((message) {
+    when(transport.latestRequest.responseHeaders).thenReturn(responseHeaders);
-      expect(message, TypeMatcher<GrpcMetadata>());
+    when(transport.latestRequest.getResponseHeader('Content-Type'))
-      if (message is GrpcMetadata) {
+        .thenReturn('application/grpc+proto');
-        message.metadata.forEach((key, value) {
+    when(transport.latestRequest.response)
-          expect(value, metadata[key]);
+        .thenReturn(String.fromCharCodes(frame(<int>[])));
-        });
+
-      }
+    // Set expectation for request readyState and generate two readyStateChange
-    });
+    // events, so that incomingMessages stream completes.
+    final readyStates = [HttpRequest.HEADERS_RECEIVED, HttpRequest.DONE];
+    when(transport.latestRequest.readyState)
+        .thenAnswer((_) => readyStates.removeAt(0));
+    transport.latestRequest.readyStateChangeController
+        .add(readyStateChangeEvent);
+    transport.latestRequest.readyStateChangeController
+        .add(readyStateChangeEvent);
+
+    // Should be only one metadata message with headers.
+    final message = await stream.incomingMessages.single as GrpcMetadata;
+    expect(message.metadata, responseHeaders);
   });
 
   test('Stream handles trailers properly', () async {
-    final trailers = <String, String>{
+    final requestHeaders = {'parameter_1': 'value_1'};
+    final responseTrailers = <String, String>{
       'trailer_1': 'value_1',
       'trailer_2': 'value_2'
     };
@@ -228,31 +252,37 @@ void main() {
     final connection = MockXhrClientConnection();
 
     final stream = connection.makeRequest('test_path', Duration(seconds: 10),
-        {}, (error, _) => fail(error.toString()));
+        requestHeaders, (error, _) => fail(error.toString()));
 
-    final encodedTrailers = frame(trailers.entries
+    final encodedTrailers = frame(responseTrailers.entries
         .map((e) => '${e.key}:${e.value}')
         .join('\r\n')
         .codeUnits);
     encodedTrailers[0] = 0x80; // Mark this frame as trailers.
     final encodedString = String.fromCharCodes(encodedTrailers);
 
-    stream.incomingMessages.listen((message) {
-      expect(message, TypeMatcher<GrpcMetadata>());
-      if (message is GrpcMetadata) {
-        message.metadata.forEach((key, value) {
-          expect(value, trailers[key]);
-        });
-      }
-    });
     when(connection.latestRequest.getResponseHeader('Content-Type'))
         .thenReturn('application/grpc+proto');
     when(connection.latestRequest.responseHeaders).thenReturn({});
-    when(connection.latestRequest.readyState)
-        .thenReturn(HttpRequest.HEADERS_RECEIVED);
     when(connection.latestRequest.response).thenReturn(encodedString);
-    connection.latestRequest.readyStateChangeController.add(null);
+
-    connection.latestRequest.progressController.add(null);
+    // Set expectation for request readyState and generate events so that
+    // incomingMessages stream completes.
+    final readyStates = [HttpRequest.HEADERS_RECEIVED, HttpRequest.DONE];
+    when(connection.latestRequest.readyState)
+        .thenAnswer((_) => readyStates.removeAt(0));
+    connection.latestRequest.readyStateChangeController
+        .add(readyStateChangeEvent);
+    connection.latestRequest.progressController.add(progressEvent);
+    connection.latestRequest.readyStateChangeController
+        .add(readyStateChangeEvent);
+
+    // Should be two metadata messages: headers and trailers.
+    final messages =
+        await stream.incomingMessages.whereType<GrpcMetadata>().toList();
+    expect(messages.length, 2);
+    expect(messages.first.metadata, isEmpty);
+    expect(messages.last.metadata, responseTrailers);
   });
 
   test('Stream handles empty trailers properly', () async {
@@ -265,24 +295,32 @@ void main() {
     encoded[0] = 0x80; // Mark this frame as trailers.
     final encodedString = String.fromCharCodes(encoded);
 
-    stream.incomingMessages.listen((message) {
-      expect(message, TypeMatcher<GrpcMetadata>());
-      if (message is GrpcMetadata) {
-        message.metadata.isEmpty;
-      }
-    });
     when(connection.latestRequest.getResponseHeader('Content-Type'))
         .thenReturn('application/grpc+proto');
     when(connection.latestRequest.responseHeaders).thenReturn({});
-    when(connection.latestRequest.readyState)
-        .thenReturn(HttpRequest.HEADERS_RECEIVED);
     when(connection.latestRequest.response).thenReturn(encodedString);
-    connection.latestRequest.readyStateChangeController.add(null);
+
-    connection.latestRequest.progressController.add(null);
+    // Set expectation for request readyState and generate events so that
+    // incomingMessages stream completes.
+    final readyStates = [HttpRequest.HEADERS_RECEIVED, HttpRequest.DONE];
+    when(connection.latestRequest.readyState)
+        .thenAnswer((_) => readyStates.removeAt(0));
+    connection.latestRequest.readyStateChangeController
+        .add(readyStateChangeEvent);
+    connection.latestRequest.progressController.add(progressEvent);
+    connection.latestRequest.readyStateChangeController
+        .add(readyStateChangeEvent);
+
+    // Should be two metadata messages: headers and trailers.
+    final messages =
+        await stream.incomingMessages.whereType<GrpcMetadata>().toList();
+    expect(messages.length, 2);
+    expect(messages.first.metadata, isEmpty);
+    expect(messages.last.metadata, isEmpty);
   });
 
   test('Stream deserializes data properly', () async {
-    final metadata = <String, String>{
+    final requestHeaders = <String, String>{
       'parameter_1': 'value_1',
       'parameter_2': 'value_2'
     };
@@ -290,57 +328,50 @@ void main() {
     final connection = MockXhrClientConnection();
 
     final stream = connection.makeRequest('test_path', Duration(seconds: 10),
-        metadata, (error, _) => fail(error.toString()));
+        requestHeaders, (error, _) => fail(error.toString()));
     final data = List<int>.filled(10, 224);
-    final encoded = frame(data);
-    final encodedString = String.fromCharCodes(encoded);
-
-    stream.incomingMessages.listen(expectAsync1((message) {
-      if (message is GrpcData) {
-        expect(message.data, equals(data));
-      }
-    }, count: 2));
-
     when(connection.latestRequest.getResponseHeader('Content-Type'))
         .thenReturn('application/grpc+proto');
-    when(connection.latestRequest.responseHeaders).thenReturn(metadata);
+    when(connection.latestRequest.responseHeaders).thenReturn({});
+    when(connection.latestRequest.response)
+        .thenReturn(String.fromCharCodes(frame(data)));
+
+    // Set expectation for request readyState and generate events, so that
+    // incomingMessages stream completes.
+    final readyStates = [HttpRequest.HEADERS_RECEIVED, HttpRequest.DONE];
     when(connection.latestRequest.readyState)
-        .thenReturn(HttpRequest.HEADERS_RECEIVED);
+        .thenAnswer((_) => readyStates.removeAt(0));
-    when(connection.latestRequest.response).thenReturn(encodedString);
+    connection.latestRequest.readyStateChangeController
-    connection.latestRequest.readyStateChangeController.add(null);
+        .add(readyStateChangeEvent);
-    connection.latestRequest.progressController.add(null);
+    connection.latestRequest.progressController.add(progressEvent);
+    connection.latestRequest.readyStateChangeController
+        .add(readyStateChangeEvent);
+
+    // Expect a single data message.
+    final message = await stream.incomingMessages.whereType<GrpcData>().single;
+    expect(message.data, data);
   });
 
   test('GrpcError with error details in response', () async {
-    final metadata = <String, String>{
-      'parameter_1': 'value_1',
-      'parameter_2': 'value_2'
-    };
-
     final connection = MockXhrClientConnection(code: 400);
-    final errorStream = StreamController<GrpcError>();
+    final errors = <GrpcError>[];
-    connection.makeRequest('test_path', Duration(seconds: 10), metadata,
+    // The incoming messages stream never completes when there's an error, so
-        (e, _) => errorStream.add(e));
+    // using completer.
-    const errorDetails = "error details";
+    final errorReceived = Completer<void>();
-    int count = 0;
+    connection.makeRequest('test_path', Duration(seconds: 10), {}, (e, _) {
-
+      errorReceived.complete();
-    errorStream.stream.listen((error) {
+      errors.add(e);
-      expect(
-          error,
-          TypeMatcher<GrpcError>()
-              .having((e) => e.rawResponse, 'rawResponse', errorDetails));
-      count++;
-      if (count == 2) {
-        errorStream.close();
-      }
     });
-
+    const errorDetails = "error details";
     when(connection.latestRequest.getResponseHeader('Content-Type'))
         .thenReturn('application/grpc+proto');
-    when(connection.latestRequest.responseHeaders).thenReturn(metadata);
+    when(connection.latestRequest.responseHeaders).thenReturn({});
     when(connection.latestRequest.readyState).thenReturn(HttpRequest.DONE);
     when(connection.latestRequest.responseText).thenReturn(errorDetails);
-    connection.latestRequest.readyStateChangeController.add(null);
+    connection.latestRequest.readyStateChangeController
+        .add(readyStateChangeEvent);
+    await errorReceived;
+    expect(errors.single.rawResponse, errorDetails);
   });
 
   test('Stream recieves multiple messages', () async {
@@ -358,40 +389,44 @@ void main() {
       List<int>.filled(10, 224),
       List<int>.filled(5, 124)
     ];
-    final encoded = data.map((d) => frame(d));
+    final encodedStrings =
-    final encodedStrings = encoded.map((e) => String.fromCharCodes(e)).toList();
+        data.map((d) => String.fromCharCodes(frame(d))).toList();
-
-    final expectedMessages = <GrpcMessage>[
-      GrpcMetadata(metadata),
-      GrpcData(data[0]),
-      GrpcData(data[1])
-    ];
-    int i = 0;
-    stream.incomingMessages.listen(expectAsync1((message) {
-      final expectedMessage = expectedMessages[i];
-      i++;
-      expect(message.runtimeType, expectedMessage.runtimeType);
-      if (message is GrpcMetadata) {
-        expect(message.metadata, (expectedMessage as GrpcMetadata).metadata);
-      } else if (message is GrpcData) {
-        expect(message.data, (expectedMessage as GrpcData).data);
-      }
-    }, count: expectedMessages.length));
 
     when(connection.latestRequest.getResponseHeader('Content-Type'))
         .thenReturn('application/grpc+proto');
     when(connection.latestRequest.responseHeaders).thenReturn(metadata);
     when(connection.latestRequest.readyState)
         .thenReturn(HttpRequest.HEADERS_RECEIVED);
-    // At first - expected response is the first message
-    when(connection.latestRequest.response)
-        .thenAnswer((_) => encodedStrings[0]);
-    connection.latestRequest.readyStateChangeController.add(null);
-    connection.latestRequest.progressController.add(null);
 
-    // After the first call, expected response should now be both responses together
+    // At first invocation the response should be the the first message, after
-    when(connection.latestRequest.response)
+    // that first + last messages.
-        .thenAnswer((_) => encodedStrings[0] + encodedStrings[1]);
+    var first = true;
-    connection.latestRequest.progressController.add(null);
+    when(connection.latestRequest.response).thenAnswer((_) {
+      if (first) {
+        first = false;
+        return encodedStrings[0];
+      }
+      return encodedStrings[0] + encodedStrings[1];
+    });
+
+    final readyStates = [HttpRequest.HEADERS_RECEIVED, HttpRequest.DONE];
+    when(connection.latestRequest.readyState)
+        .thenAnswer((_) => readyStates.removeAt(0));
+
+    final queue = StreamQueue(stream.incomingMessages);
+    // Headers.
+    connection.latestRequest.readyStateChangeController
+        .add(readyStateChangeEvent);
+    expect(((await queue.next) as GrpcMetadata).metadata, metadata);
+    // Data 1.
+    connection.latestRequest.progressController.add(progressEvent);
+    expect(((await queue.next) as GrpcData).data, data[0]);
+    // Data 2.
+    connection.latestRequest.progressController.add(progressEvent);
+    expect(((await queue.next) as GrpcData).data, data[1]);
+    // Done.
+    connection.latestRequest.readyStateChangeController
+        .add(readyStateChangeEvent);
+    expect(await queue.hasNext, isFalse);
   });
 }

test/connection_server_test.dart

@@ -25,7 +25,7 @@ import 'src/server_utils.dart';
 void main() {
   const dummyValue = 17;
 
-  ConnectionServerHarness harness;
+  late ConnectionServerHarness harness;
 
   setUp(() {
     harness = ConnectionServerHarness()..setUp();
@@ -257,7 +257,7 @@ void main() {
     harness
       ..service.unaryHandler = methodHandler
       ..fromServer.stream.listen(expectAsync1((_) {}, count: 0),
-          onError: expectAsync1((error) {
+          onError: expectAsync1((dynamic error) {
             expect(error, 'TERMINATED');
           }, count: 1),
           onDone: expectAsync0(() {}, count: 1))

test/grpc_web_test.dart

@@ -11,7 +11,7 @@ import 'package:grpc/grpc_web.dart';
 import 'src/generated/echo.pbgrpc.dart';
 
 void main() {
-  GrpcWebServer server;
+  late GrpcWebServer server;
 
   setUpAll(() async {
     server = await GrpcWebServer.start();

test/options_test.dart

@@ -13,6 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 @TestOn('vm')
+
 import 'dart:io';
 
 import 'package:grpc/src/client/transport/http2_credentials.dart';

test/round_trip_test.dart

@@ -16,7 +16,7 @@ class TestClient extends Client {
       (int value) => [value], (List<int> value) => value[0]);
 
   TestClient(api.ClientChannel channel) : super(channel);
-  ResponseStream<int> stream(int request, {CallOptions options}) {
+  ResponseStream<int> stream(int request, {CallOptions? options}) {
     return $createStreamingCall(_$stream, Stream.value(request),
         options: options);
   }
@@ -66,7 +66,7 @@ main() async {
 
     final channel = FixedConnectionClientChannel(Http2ClientConnection(
       address,
-      server.port,
+      server.port!,
       ChannelOptions(credentials: ChannelCredentials.insecure()),
     ));
     final testClient = TestClient(channel);
@@ -83,7 +83,7 @@ main() async {
 
     final channel = FixedConnectionClientChannel(Http2ClientConnection(
       address,
-      server.port,
+      server.port!,
       ChannelOptions(
         credentials: ChannelCredentials.insecure(),
         codecRegistry: CodecRegistry(codecs: const [GzipCodec()]),
@@ -111,7 +111,7 @@ main() async {
 
     final channel = FixedConnectionClientChannel(Http2ClientConnection(
       address,
-      server.port,
+      server.port!,
       ChannelOptions(
           credentials: ChannelCredentials.secure(
               certificates: File('test/data/localhost.crt').readAsBytesSync(),
@@ -129,7 +129,7 @@ main() async {
 
     final channel = FixedConnectionClientChannel(Http2ClientConnection(
       'localhost',
-      server.port,
+      server.port!,
       ChannelOptions(credentials: ChannelCredentials.insecure()),
     ));
     final testClient = TestClient(channel);
@@ -145,7 +145,7 @@ main() async {
 
     final channel = FixedConnectionClientChannel(Http2ClientConnection(
       'localhost',
-      server.port,
+      server.port!,
       ChannelOptions(credentials: ChannelCredentials.insecure()),
     ));
     final testClient = TestClient(channel);

test/server_handles_broken_connection_test.dart

@@ -14,7 +14,7 @@ class TestClient extends grpc.Client {
 
   TestClient(grpc.ClientChannel channel) : super(channel);
   grpc.ResponseStream<int> infiniteStream(int request,
-      {grpc.CallOptions options}) {
+      {grpc.CallOptions? options}) {
     return $createStreamingCall(_$infiniteStream, Stream.value(request),
         options: options);
   }
@@ -24,12 +24,13 @@ class TestService extends grpc.Service {
   String get $name => 'test.TestService';
   final void Function() finallyCallback;
 
-  TestService({this.finallyCallback}) {
+  TestService({required this.finallyCallback}) {
     $addMethod(grpc.ServiceMethod<int, int>('infiniteStream', infiniteStream,
         false, true, (List<int> value) => value[0], (int value) => [value]));
   }
 
-  Stream<int> infiniteStream(grpc.ServiceCall call, Future request) async* {
+  Stream<int> infiniteStream(
+      grpc.ServiceCall call, Future<int> request) async* {
     int count = await request;
     try {
       while (true) {
@@ -50,7 +51,8 @@ class ClientData {
   final InternetAddress address;
   final int port;
   final SendPort sendPort;
-  ClientData({this.address, this.port, this.sendPort});
+  ClientData(
+      {required this.address, required this.port, required this.sendPort});
 }
 
 void client(clientData) async {
@@ -73,7 +75,7 @@ main() async {
       "the client interrupting the connection does not crash the server",
       (address) async {
     // interrrupt the connect of client, the server does not crash.
-    grpc.Server server;
+    late grpc.Server server;
     server = grpc.Server([
       TestService(
           finallyCallback: expectAsync0(() {
@@ -86,7 +88,7 @@ main() async {
         client,
         ClientData(
             address: address,
-            port: server.port,
+            port: server.port!,
             sendPort: receivePort.sendPort));
     receivePort.listen(expectAsync1((e) {
       expect(e, isA<grpc.GrpcError>());

test/server_test.dart

@@ -25,7 +25,7 @@ import 'src/server_utils.dart';
 void main() {
   const dummyValue = 17;
 
-  ServerHarness harness;
+  late ServerHarness harness;
 
   setUp(() {
     harness = ServerHarness()..setUp();
@@ -271,7 +271,7 @@ void main() {
     harness
       ..service.unaryHandler = methodHandler
       ..fromServer.stream.listen(expectAsync1((_) {}, count: 0),
-          onError: expectAsync1((error) {
+          onError: expectAsync1((dynamic error) {
             expect(error, 'TERMINATED');
           }, count: 1),
           onDone: expectAsync0(() {}, count: 1))

test/src/client_utils.dart

@@ -21,15 +21,14 @@ import 'package:grpc/src/client/channel.dart' as base;
 import 'package:grpc/src/client/http2_connection.dart';
 import 'package:grpc/src/shared/message.dart';
 import 'package:http2/transport.dart';
+import 'package:mockito/annotations.dart';
 import 'package:mockito/mockito.dart';
 import 'package:test/test.dart';
 
+import 'client_utils.mocks.dart';
 import 'utils.dart';
 
-class MockTransport extends Mock implements ClientTransportConnection {}
+@GenerateMocks([ClientTransportConnection, ClientTransportStream])
-
-class MockStream extends Mock implements ClientTransportStream {}
-
 class FakeConnection extends Http2ClientConnection {
   final ClientTransportConnection transport;
 
@@ -60,7 +59,7 @@ class FakeClientTransportConnection extends Http2ClientConnection {
   }
 }
 
-Duration testBackoff(Duration lastBackoff) => const Duration(milliseconds: 1);
+Duration testBackoff(Duration? lastBackoff) => const Duration(milliseconds: 1);
 
 class FakeChannelOptions implements ChannelOptions {
   ChannelCredentials credentials = const ChannelCredentials.secure();
@@ -97,16 +96,16 @@ class FakeClientConnectorChannel extends ClientTransportConnectorChannel {
 typedef ServerMessageHandler = void Function(StreamMessage message);
 
 class TestClient extends Client {
-  ClientMethod<int, int> _$unary;
+  late ClientMethod<int, int> _$unary;
-  ClientMethod<int, int> _$clientStreaming;
+  late ClientMethod<int, int> _$clientStreaming;
-  ClientMethod<int, int> _$serverStreaming;
+  late ClientMethod<int, int> _$serverStreaming;
-  ClientMethod<int, int> _$bidirectional;
+  late ClientMethod<int, int> _$bidirectional;
 
   final int Function(List<int> value) decode;
 
   TestClient(base.ClientChannel channel,
-      {CallOptions options,
+      {CallOptions? options,
-      Iterable<ClientInterceptor> interceptors,
+      Iterable<ClientInterceptor>? interceptors,
       this.decode: mockDecode})
       : super(channel, options: options, interceptors: interceptors) {
     _$unary = ClientMethod<int, int>('/Test/Unary', mockEncode, decode);
@@ -118,34 +117,34 @@ class TestClient extends Client {
         ClientMethod<int, int>('/Test/Bidirectional', mockEncode, decode);
   }
 
-  ResponseFuture<int> unary(int request, {CallOptions options}) {
+  ResponseFuture<int> unary(int request, {CallOptions? options}) {
     return $createUnaryCall(_$unary, request, options: options);
   }
 
   ResponseFuture<int> clientStreaming(Stream<int> request,
-      {CallOptions options}) {
+      {CallOptions? options}) {
     return $createStreamingCall(_$clientStreaming, request, options: options)
         .single;
   }
 
-  ResponseStream<int> serverStreaming(int request, {CallOptions options}) {
+  ResponseStream<int> serverStreaming(int request, {CallOptions? options}) {
     return $createStreamingCall(_$serverStreaming, Stream.value(request),
         options: options);
   }
 
   ResponseStream<int> bidirectional(Stream<int> request,
-      {CallOptions options}) {
+      {CallOptions? options}) {
     return $createStreamingCall(_$bidirectional, request, options: options);
   }
 }
 
 class ClientHarness extends _Harness {
-  FakeConnection connection;
+  FakeConnection? connection;
 
   @override
   FakeChannel createChannel() {
     connection = FakeConnection('test', transport, channelOptions);
-    return FakeChannel('test', connection, channelOptions);
+    return FakeChannel('test', connection!, channelOptions);
   }
 
   @override
@@ -153,14 +152,14 @@ class ClientHarness extends _Harness {
 }
 
 class ClientTransportConnectorHarness extends _Harness {
-  FakeClientTransportConnection connection;
+  FakeClientTransportConnection? connection;
-  ClientTransportConnector connector;
+  late ClientTransportConnector connector;
 
   @override
   FakeClientConnectorChannel createChannel() {
     connector = FakeClientTransportConnector(transport);
     connection = FakeClientTransportConnection(connector, channelOptions);
-    return FakeClientConnectorChannel(connector, connection, channelOptions);
+    return FakeClientConnectorChannel(connector, connection!, channelOptions);
   }
 
   @override
@@ -187,27 +186,27 @@ class FakeClientTransportConnector extends ClientTransportConnector {
 }
 
 abstract class _Harness {
-  MockTransport transport;
+  late MockClientTransportConnection transport;
-  base.ClientChannel channel;
+  late base.ClientChannel channel;
-  FakeChannelOptions channelOptions;
+  late FakeChannelOptions channelOptions;
-  MockStream stream;
+  late MockClientTransportStream stream;
 
-  StreamController<StreamMessage> fromClient;
+  late StreamController<StreamMessage> fromClient;
-  StreamController<StreamMessage> toClient;
+  late StreamController<StreamMessage> toClient;
 
-  Iterable<ClientInterceptor> interceptors;
+  Iterable<ClientInterceptor>? interceptors;
 
-  TestClient client;
+  late TestClient client;
 
   base.ClientChannel createChannel();
 
   String get expectedAuthority;
 
   void setUp() {
-    transport = MockTransport();
+    transport = MockClientTransportConnection();
     channelOptions = FakeChannelOptions();
     channel = createChannel();
-    stream = MockStream();
+    stream = MockClientTransportStream();
     fromClient = StreamController();
     toClient = StreamController();
     when(transport.makeRequest(any, endStream: anyNamed('endStream')))
@@ -216,6 +215,8 @@ abstract class _Harness {
     when(transport.isOpen).thenReturn(true);
     when(stream.outgoingMessages).thenReturn(fromClient.sink);
     when(stream.incomingMessages).thenAnswer((_) => toClient.stream);
+    when(stream.terminate()).thenReturn(null);
+    when(transport.finish()).thenAnswer((_) async {});
     client = TestClient(channel, interceptors: interceptors);
   }
 
@@ -246,13 +247,13 @@ abstract class _Harness {
   }
 
   Future<void> runTest(
-      {Future clientCall,
+      {Future? clientCall,
       dynamic expectedResult,
-      String expectedPath,
+      String? expectedPath,
-      Duration expectedTimeout,
+      Duration? expectedTimeout,
-      Map<String, String> expectedCustomHeaders,
+      Map<String, String>? expectedCustomHeaders,
       List<MessageHandler> serverHandlers = const [],
-      Function doneHandler,
+      void Function()? doneHandler,
       bool expectDone = true}) async {
     int serverHandlerIndex = 0;
     void handleServerMessage(StreamMessage message) {
@@ -261,7 +262,7 @@ abstract class _Harness {
 
     final clientSubscription = fromClient.stream.listen(
         expectAsync1(handleServerMessage, count: serverHandlers.length),
-        onError: expectAsync1((_) {}, count: 0),
+        onError: expectAsync1((dynamic _) {}, count: 0),
         onDone: expectAsync0(doneHandler ?? () {}, count: expectDone ? 1 : 0));
 
     final result = await clientCall;
@@ -276,13 +277,14 @@ abstract class _Harness {
             MapEntry(utf8.decode(header.name), utf8.decode(header.value)))),
         path: expectedPath,
         authority: expectedAuthority,
-        timeout: toTimeoutString(expectedTimeout),
+        timeout:
+            expectedTimeout == null ? null : toTimeoutString(expectedTimeout),
         customHeaders: expectedCustomHeaders);
 
     await clientSubscription.cancel();
   }
 
-  Future<void> expectThrows(Future future, dynamic exception) async {
+  Future<void> expectThrows(Future? future, dynamic exception) async {
     try {
       await future;
       fail('Did not throw');
@@ -293,11 +295,11 @@ abstract class _Harness {
   }
 
   Future<void> runFailureTest(
-      {Future clientCall,
+      {Future? clientCall,
       dynamic expectedException,
-      String expectedPath,
+      String? expectedPath,
-      Duration expectedTimeout,
+      Duration? expectedTimeout,
-      Map<String, String> expectedCustomHeaders,
+      Map<String, String>? expectedCustomHeaders,
       List<MessageHandler> serverHandlers = const [],
       bool expectDone = true}) async {
     return runTest(

test/src/client_utils.mocks.dart

@@ -0,0 +1,91 @@
+import 'dart:async' as _i3;
+
+import 'package:http2/src/hpack/hpack.dart' as _i4;
+import 'package:http2/transport.dart' as _i2;
+import 'package:mockito/mockito.dart' as _i1;
+
+// ignore_for_file: comment_references
+
+// ignore_for_file: unnecessary_parenthesis
+
+class _FakeClientTransportStream extends _i1.Fake
+    implements _i2.ClientTransportStream {}
+
+class _FakeStreamSink<S> extends _i1.Fake implements _i3.StreamSink<S> {}
+
+/// A class which mocks [ClientTransportConnection].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockClientTransportConnection extends _i1.Mock
+    implements _i2.ClientTransportConnection {
+  MockClientTransportConnection() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  bool get isOpen =>
+      (super.noSuchMethod(Invocation.getter(#isOpen), false) as bool);
+  @override
+  set onActiveStateChanged(_i2.ActiveStateHandler? callback) =>
+      super.noSuchMethod(Invocation.setter(#onActiveStateChanged, callback));
+  @override
+  _i3.Future<void> get onInitialPeerSettingsReceived => (super.noSuchMethod(
+          Invocation.getter(#onInitialPeerSettingsReceived), Future.value(null))
+      as _i3.Future<void>);
+  @override
+  _i2.ClientTransportStream makeRequest(List<_i4.Header>? headers,
+          {bool? endStream = false}) =>
+      (super.noSuchMethod(
+          Invocation.method(#makeRequest, [headers], {#endStream: endStream}),
+          _FakeClientTransportStream()) as _i2.ClientTransportStream);
+  @override
+  _i3.Future<dynamic> ping() =>
+      (super.noSuchMethod(Invocation.method(#ping, []), Future.value(null))
+          as _i3.Future<dynamic>);
+  @override
+  _i3.Future<dynamic> finish() =>
+      (super.noSuchMethod(Invocation.method(#finish, []), Future.value(null))
+          as _i3.Future<dynamic>);
+  @override
+  _i3.Future<dynamic> terminate() =>
+      (super.noSuchMethod(Invocation.method(#terminate, []), Future.value(null))
+          as _i3.Future<dynamic>);
+}
+
+/// A class which mocks [ClientTransportStream].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockClientTransportStream extends _i1.Mock
+    implements _i2.ClientTransportStream {
+  MockClientTransportStream() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  _i3.Stream<_i2.TransportStreamPush> get peerPushes => (super.noSuchMethod(
+          Invocation.getter(#peerPushes),
+          Stream<_i2.TransportStreamPush>.empty())
+      as _i3.Stream<_i2.TransportStreamPush>);
+  @override
+  int get id => (super.noSuchMethod(Invocation.getter(#id), 0) as int);
+  @override
+  _i3.Stream<_i2.StreamMessage> get incomingMessages => (super.noSuchMethod(
+      Invocation.getter(#incomingMessages),
+      Stream<_i2.StreamMessage>.empty()) as _i3.Stream<_i2.StreamMessage>);
+  @override
+  _i3.StreamSink<_i2.StreamMessage> get outgoingMessages => (super.noSuchMethod(
+          Invocation.getter(#outgoingMessages),
+          _FakeStreamSink<_i2.StreamMessage>())
+      as _i3.StreamSink<_i2.StreamMessage>);
+  @override
+  set onTerminated(void Function(int?)? value) =>
+      super.noSuchMethod(Invocation.setter(#onTerminated, value));
+  @override
+  void sendHeaders(List<_i4.Header>? headers, {bool? endStream = false}) =>
+      super.noSuchMethod(
+          Invocation.method(#sendHeaders, [headers], {#endStream: endStream}));
+  @override
+  void sendData(List<int>? bytes, {bool? endStream = false}) =>
+      super.noSuchMethod(
+          Invocation.method(#sendData, [bytes], {#endStream: endStream}));
+}

test/src/generated/echo.pb.dart

@@ -2,7 +2,7 @@
 //  Generated code. Do not modify.
 //  source: echo.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
 import 'dart:core' as $core;
@@ -27,7 +27,15 @@ class EchoRequest extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   EchoRequest._() : super();
-  factory EchoRequest() => create();
+  factory EchoRequest({
+    $core.String? message,
+  }) {
+    final _result = create();
+    if (message != null) {
+      _result.message = message;
+    }
+    return _result;
+  }
   factory EchoRequest.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -42,8 +50,8 @@ class EchoRequest extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   EchoRequest copyWith(void Function(EchoRequest) updates) =>
-      super.copyWith((message) =>
+      super.copyWith((message) => updates(message as EchoRequest))
-          updates(message as EchoRequest)); // ignore: deprecated_member_use
+          as EchoRequest; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static EchoRequest create() => EchoRequest._();
@@ -52,7 +60,7 @@ class EchoRequest extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static EchoRequest getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<EchoRequest>(create);
-  static EchoRequest _defaultInstance;
+  static EchoRequest? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get message => $_getSZ(0);
@@ -85,7 +93,15 @@ class EchoResponse extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   EchoResponse._() : super();
-  factory EchoResponse() => create();
+  factory EchoResponse({
+    $core.String? message,
+  }) {
+    final _result = create();
+    if (message != null) {
+      _result.message = message;
+    }
+    return _result;
+  }
   factory EchoResponse.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -100,8 +116,8 @@ class EchoResponse extends $pb.GeneratedMessage {
       'Use [GeneratedMessageGenericExtensions.rebuild] instead. '
       'Will be removed in next major version')
   EchoResponse copyWith(void Function(EchoResponse) updates) =>
-      super.copyWith((message) =>
+      super.copyWith((message) => updates(message as EchoResponse))
-          updates(message as EchoResponse)); // ignore: deprecated_member_use
+          as EchoResponse; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static EchoResponse create() => EchoResponse._();
@@ -111,7 +127,7 @@ class EchoResponse extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static EchoResponse getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<EchoResponse>(create);
-  static EchoResponse _defaultInstance;
+  static EchoResponse? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get message => $_getSZ(0);
@@ -156,7 +172,23 @@ class ServerStreamingEchoRequest extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   ServerStreamingEchoRequest._() : super();
-  factory ServerStreamingEchoRequest() => create();
+  factory ServerStreamingEchoRequest({
+    $core.String? message,
+    $core.int? messageCount,
+    $core.int? messageInterval,
+  }) {
+    final _result = create();
+    if (message != null) {
+      _result.message = message;
+    }
+    if (messageCount != null) {
+      _result.messageCount = messageCount;
+    }
+    if (messageInterval != null) {
+      _result.messageInterval = messageInterval;
+    }
+    return _result;
+  }
   factory ServerStreamingEchoRequest.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -173,8 +205,9 @@ class ServerStreamingEchoRequest extends $pb.GeneratedMessage {
       'Will be removed in next major version')
   ServerStreamingEchoRequest copyWith(
           void Function(ServerStreamingEchoRequest) updates) =>
-      super.copyWith((message) => updates(message
+      super.copyWith(
-          as ServerStreamingEchoRequest)); // ignore: deprecated_member_use
+              (message) => updates(message as ServerStreamingEchoRequest))
+          as ServerStreamingEchoRequest; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static ServerStreamingEchoRequest create() => ServerStreamingEchoRequest._();
@@ -184,7 +217,7 @@ class ServerStreamingEchoRequest extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static ServerStreamingEchoRequest getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<ServerStreamingEchoRequest>(create);
-  static ServerStreamingEchoRequest _defaultInstance;
+  static ServerStreamingEchoRequest? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get message => $_getSZ(0);
@@ -241,7 +274,15 @@ class ServerStreamingEchoResponse extends $pb.GeneratedMessage {
     ..hasRequiredFields = false;
 
   ServerStreamingEchoResponse._() : super();
-  factory ServerStreamingEchoResponse() => create();
+  factory ServerStreamingEchoResponse({
+    $core.String? message,
+  }) {
+    final _result = create();
+    if (message != null) {
+      _result.message = message;
+    }
+    return _result;
+  }
   factory ServerStreamingEchoResponse.fromBuffer($core.List<$core.int> i,
           [$pb.ExtensionRegistry r = $pb.ExtensionRegistry.EMPTY]) =>
       create()..mergeFromBuffer(i, r);
@@ -258,8 +299,9 @@ class ServerStreamingEchoResponse extends $pb.GeneratedMessage {
       'Will be removed in next major version')
   ServerStreamingEchoResponse copyWith(
           void Function(ServerStreamingEchoResponse) updates) =>
-      super.copyWith((message) => updates(message
+      super.copyWith(
-          as ServerStreamingEchoResponse)); // ignore: deprecated_member_use
+              (message) => updates(message as ServerStreamingEchoResponse))
+          as ServerStreamingEchoResponse; // ignore: deprecated_member_use
   $pb.BuilderInfo get info_ => _i;
   @$core.pragma('dart2js:noInline')
   static ServerStreamingEchoResponse create() =>
@@ -270,7 +312,7 @@ class ServerStreamingEchoResponse extends $pb.GeneratedMessage {
   @$core.pragma('dart2js:noInline')
   static ServerStreamingEchoResponse getDefault() => _defaultInstance ??=
       $pb.GeneratedMessage.$_defaultFor<ServerStreamingEchoResponse>(create);
-  static ServerStreamingEchoResponse _defaultInstance;
+  static ServerStreamingEchoResponse? _defaultInstance;
 
   @$pb.TagNumber(1)
   $core.String get message => $_getSZ(0);

test/src/generated/echo.pbenum.dart

@@ -2,5 +2,5 @@
 //  Generated code. Do not modify.
 //  source: echo.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields

test/src/generated/echo.pbgrpc.dart

@@ -2,7 +2,7 @@
 //  Generated code. Do not modify.
 //  source: echo.proto
 //
-// @dart = 2.3
+
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
 import 'dart:async' as $async;
@@ -26,18 +26,18 @@ class EchoServiceClient extends $grpc.Client {
           $0.ServerStreamingEchoResponse.fromBuffer(value));
 
   EchoServiceClient($grpc.ClientChannel channel,
-      {$grpc.CallOptions options,
+      {$grpc.CallOptions? options,
-      $core.Iterable<$grpc.ClientInterceptor> interceptors})
+      $core.Iterable<$grpc.ClientInterceptor>? interceptors})
       : super(channel, options: options, interceptors: interceptors);
 
   $grpc.ResponseFuture<$0.EchoResponse> echo($0.EchoRequest request,
-      {$grpc.CallOptions options}) {
+      {$grpc.CallOptions? options}) {
     return $createUnaryCall(_$echo, request, options: options);
   }
 
   $grpc.ResponseStream<$0.ServerStreamingEchoResponse> serverStreamingEcho(
       $0.ServerStreamingEchoRequest request,
-      {$grpc.CallOptions options}) {
+      {$grpc.CallOptions? options}) {
     return $createStreamingCall(
         _$serverStreamingEcho, $async.Stream.fromIterable([request]),
         options: options);

test/src/generated/echo.pbjson.dart

@@ -2,9 +2,11 @@
 //  Generated code. Do not modify.
 //  source: echo.proto
 //
-// @dart = 2.3
+// @dart = 2.12
 // ignore_for_file: annotate_overrides,camel_case_types,unnecessary_const,non_constant_identifier_names,library_prefixes,unused_import,unused_shown_name,return_of_invalid_type,unnecessary_this,prefer_final_fields
 
+import 'dart:core' as $core;
+
 const EchoRequest$json = const {
   '1': 'EchoRequest',
   '2': const [

test/src/server_utils.dart

@@ -27,12 +27,12 @@ class TestService extends Service {
   @override
   String get $name => 'Test';
 
-  Future<int> Function(ServiceCall call, Future<int> request) unaryHandler;
+  Future<int> Function(ServiceCall call, Future<int> request)? unaryHandler;
-  Future<int> Function(ServiceCall call, Stream<int> request)
+  Future<int> Function(ServiceCall call, Stream<int> request)?
       clientStreamingHandler;
-  Stream<int> Function(ServiceCall call, Future<int> request)
+  Stream<int> Function(ServiceCall call, Future<int> request)?
       serverStreamingHandler;
-  Stream<int> Function(ServiceCall call, Stream<int> request)
+  Stream<int> Function(ServiceCall call, Stream<int> request)?
       bidirectionalHandler;
 
   TestService() {
@@ -53,40 +53,40 @@ class TestService extends Service {
     if (unaryHandler == null) {
       fail('Should not invoke Unary');
     }
-    return unaryHandler(call, request);
+    return unaryHandler!(call, request);
   }
 
   Future<int> _clientStreaming(ServiceCall call, Stream<int> request) {
     if (clientStreamingHandler == null) {
       fail('Should not invoke ClientStreaming');
     }
-    return clientStreamingHandler(call, request);
+    return clientStreamingHandler!(call, request);
   }
 
   Stream<int> _serverStreaming(ServiceCall call, Future<int> request) {
     if (serverStreamingHandler == null) {
       fail('Should not invoke ServerStreaming');
     }
-    return serverStreamingHandler(call, request);
+    return serverStreamingHandler!(call, request);
   }
 
   Stream<int> _bidirectional(ServiceCall call, Stream<int> request) {
     if (bidirectionalHandler == null) {
       fail('Should not invoke Bidirectional');
     }
-    return bidirectionalHandler(call, request);
+    return bidirectionalHandler!(call, request);
   }
 }
 
 class TestInterceptor {
-  Interceptor handler;
+  Interceptor? handler;
 
-  FutureOr<GrpcError> call(ServiceCall call, ServiceMethod method) {
+  FutureOr<GrpcError?> call(ServiceCall call, ServiceMethod method) {
     if (handler == null) {
       return null;
     }
 
-    return handler(call, method);
+    return handler!(call, method);
   }
 }
 
@@ -112,7 +112,8 @@ class TestServerStream extends ServerTransportStream {
   bool get canPush => true;
 
   @override
-  ServerTransportStream push(List<Header> requestHeaders) => null;
+  ServerTransportStream push(List<Header> requestHeaders) =>
+      throw 'unimplemented';
 }
 
 class ServerHarness extends _Harness {
@@ -144,7 +145,7 @@ abstract class _Harness {
   final fromServer = StreamController<StreamMessage>();
   final service = TestService();
   final interceptor = TestInterceptor();
-  ConnectionServer _server;
+  ConnectionServer? _server;
 
   ConnectionServer createServer();
 
@@ -168,7 +169,7 @@ abstract class _Harness {
 
     fromServer.stream.listen(
         expectAsync1(handleMessages, count: handlers.length),
-        onError: expectAsync1((_) {}, count: 0),
+        onError: expectAsync1((dynamic _) {}, count: 0),
         onDone: expectAsync0(() {}, count: 1));
   }
 
@@ -185,8 +186,8 @@ abstract class _Harness {
 
   void sendRequestHeader(String path,
       {String authority = 'test',
-      Map<String, String> metadata,
+      Map<String, String>? metadata,
-      Duration timeout}) {
+      Duration? timeout}) {
     final headers = Http2ClientConnection.createCallHeaders(
         true, authority, path, timeout, metadata, null,
         userAgent: 'dart-grpc/1.0.0 test');

test/src/utils.dart

@@ -31,10 +31,10 @@ Map<String, String> headersToMap(List<Header> headers) =>
         key: (h) => ascii.decode(h.name), value: (h) => ascii.decode(h.value));
 
 void validateRequestHeaders(Map<String, String> headers,
-    {String path,
+    {String? path,
     String authority = 'test',
-    String timeout,
+    String? timeout,
-    Map<String, String> customHeaders}) {
+    Map<String, String>? customHeaders}) {
   expect(headers[':method'], 'POST');
   expect(headers[':scheme'], 'https');
   if (path != null) {
@@ -54,7 +54,7 @@ void validateRequestHeaders(Map<String, String> headers,
 void validateResponseHeaders(Map<String, String> headers,
     {int status = 200,
     bool allowTrailers = false,
-    Map<String, String> customHeaders}) {
+    Map<String, String>? customHeaders}) {
   expect(headers[':status'], '200');
   expect(headers['content-type'], startsWith('application/grpc'));
   if (!allowTrailers) {
@@ -67,7 +67,7 @@ void validateResponseHeaders(Map<String, String> headers,
 }
 
 void validateResponseTrailers(Map<String, String> trailers,
-    {int status = 0, String message, Map<String, String> customTrailers}) {
+    {int status = 0, String? message, Map<String, String>? customTrailers}) {
   expect(trailers['grpc-status'], '$status');
   if (message != null) {
     expect(trailers['grpc-message'], message);
@@ -84,7 +84,7 @@ GrpcMetadata validateMetadataMessage(StreamMessage message,
 
   final decoded = GrpcHttpDecoder().convert(message);
   expect(decoded, TypeMatcher<GrpcMetadata>());
-  return decoded;
+  return decoded as GrpcMetadata;
 }
 
 GrpcData validateDataMessage(StreamMessage message, {bool endStream = false}) {
@@ -93,7 +93,7 @@ GrpcData validateDataMessage(StreamMessage message, {bool endStream = false}) {
 
   final decoded = GrpcHttpDecoder().convert(message);
   expect(decoded, TypeMatcher<GrpcData>());
-  return decoded;
+  return decoded as GrpcData;
 }
 
 void Function(StreamMessage message) headerValidator() {

test/stream_test.dart

@@ -22,8 +22,8 @@ import 'package:grpc/grpc.dart';
 
 void main() {
   group('GrpcHttpDecoder', () {
-    StreamController<StreamMessage> input;
+    late StreamController<StreamMessage> input;
-    Stream<GrpcMessage> output;
+    late Stream<GrpcMessage> output;
 
     setUp(() {
       input = StreamController();
@@ -51,11 +51,12 @@ void main() {
       }
 
       expect(converted[0], TypeMatcher<GrpcMetadata>());
-      verify(converted[1], [48, 49, 50, 51, 52, 53, 54, 55, 56, 57]);
+      verify(
-      verify(converted[2], [97, 98, 99, 100]);
+          converted[1] as GrpcData, [48, 49, 50, 51, 52, 53, 54, 55, 56, 57]);
-      verify(converted[3], [65]);
+      verify(converted[2] as GrpcData, [97, 98, 99, 100]);
-      verify(converted[4], [48, 49, 50, 51]);
+      verify(converted[3] as GrpcData, [65]);
-      verify(converted[5], List.filled(256, 90));
+      verify(converted[4] as GrpcData, [48, 49, 50, 51]);
+      verify(converted[5] as GrpcData, List.filled(256, 90));
     });
 
     test('throws error if input is closed while receiving data header',

test/timeline_test.dart

@@ -33,7 +33,7 @@ class TestClient extends Client {
       path, (int value) => [value], (List<int> value) => value[0]);
 
   TestClient(api.ClientChannel channel) : super(channel);
-  ResponseStream<int> stream(int request, {CallOptions options}) {
+  ResponseStream<int> stream(int request, {CallOptions? options}) {
     return $createStreamingCall(_$stream, Stream.fromIterable([request]),
         options: options);
   }
@@ -69,12 +69,12 @@ class FakeTimelineTask extends Fake implements TimelineTask {
   static final List<Map> events = [];
   static int _idCount = 0;
 
-  final String filterKey;
+  final String? filterKey;
-  final TimelineTask parent;
+  final TimelineTask? parent;
   final int id = _idCount++;
   int _startFinishCount = 0;
 
-  factory FakeTimelineTask({TimelineTask parent, String filterKey}) {
+  factory FakeTimelineTask({TimelineTask? parent, String? filterKey}) {
     final task = FakeTimelineTask._(parent: parent, filterKey: filterKey);
     tasks.add(task);
     return task;
@@ -84,7 +84,7 @@ class FakeTimelineTask extends Fake implements TimelineTask {
 
   bool get isComplete => _startFinishCount == 0;
 
-  void start(String name, {Map arguments}) {
+  void start(String name, {Map? arguments}) {
     events.add({
       'id': id,
       'ph': 'b',
@@ -98,7 +98,7 @@ class FakeTimelineTask extends Fake implements TimelineTask {
     ++_startFinishCount;
   }
 
-  void instant(String name, {Map arguments}) {
+  void instant(String name, {Map? arguments}) {
     events.add({
       'id': id,
       'ph': 'i',
@@ -110,7 +110,7 @@ class FakeTimelineTask extends Fake implements TimelineTask {
     });
   }
 
-  void finish({Map arguments}) {
+  void finish({Map? arguments}) {
     events.add({
       'id': id,
       'ph': 'e',
@@ -124,7 +124,8 @@ class FakeTimelineTask extends Fake implements TimelineTask {
   }
 }
 
-TimelineTask fakeTimelineTaskFactory({String filterKey, TimelineTask parent}) =>
+TimelineTask fakeTimelineTaskFactory(
+        {String? filterKey, TimelineTask? parent}) =>
     FakeTimelineTask(filterKey: filterKey, parent: parent);
 
 testee() async {
@@ -134,7 +135,7 @@ testee() async {
   timelineTaskFactory = fakeTimelineTaskFactory;
   final channel = FixedConnectionClientChannel(Http2ClientConnection(
     'localhost',
-    server.port,
+    server.port!,
     ChannelOptions(credentials: ChannelCredentials.insecure()),
   ));
   final testClient = TestClient(channel);

test/timeout_test.dart

@@ -28,7 +28,6 @@ void main() {
 
   group('Unit:', () {
     test('Timeouts are converted correctly to header string', () {
-      expect(toTimeoutString(null), isNull);
       expect(toTimeoutString(Duration(microseconds: -1)), '1n');
       expect(toTimeoutString(Duration(microseconds: 0)), '0u');
       expect(toTimeoutString(Duration(microseconds: 107)), '107u');
@@ -61,7 +60,7 @@ void main() {
   });
 
   group('Client:', () {
-    ClientHarness harness;
+    late ClientHarness harness;
 
     setUp(() {
       harness = ClientHarness()..setUp();
@@ -101,7 +100,7 @@ void main() {
   });
 
   group('Server:', () {
-    ServerHarness harness;
+    late ServerHarness harness;
 
     setUp(() {
       harness = ServerHarness()..setUp();
@@ -112,6 +111,7 @@ void main() {
     });
 
     test('Calls time out if deadline is exceeded', () async {
+      final handlerFinished = Completer<void>();
       Future<int> methodHandler(ServiceCall call, Future<int> request) async {
         try {
           expect(call.isTimedOut, isFalse);
@@ -126,6 +126,8 @@ void main() {
           fail('Did not throw');
         } catch (error, stack) {
           registerException(error, stack);
+        } finally {
+          handlerFinished.complete();
         }
         return dummyValue;
       }
@@ -134,7 +136,7 @@ void main() {
         ..service.unaryHandler = methodHandler
         ..expectErrorResponse(StatusCode.deadlineExceeded, 'Deadline exceeded')
         ..sendRequestHeader('/Test/Unary', timeout: Duration(microseconds: 1));
-      await harness.fromServer.done;
+      await Future.wait([handlerFinished.future, harness.fromServer.done]);
     });
   }, testOn: 'vm');
 }