diff --git a/lib/src/client/call.dart b/lib/src/client/call.dart
index aed328f..9760a41 100644
--- a/lib/src/client/call.dart
+++ b/lib/src/client/call.dart
@@ -15,8 +15,8 @@
 
 import 'dart:async';
 
-import '../shared/status.dart';
 import '../shared/message.dart';
+import '../shared/status.dart';
 
 import 'common.dart';
 import 'connection.dart';
diff --git a/lib/src/client/http2_channel.dart b/lib/src/client/http2_channel.dart
index 9fc5710..e9ef760 100644
--- a/lib/src/client/http2_channel.dart
+++ b/lib/src/client/http2_channel.dart
@@ -13,12 +13,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+import 'dart:async';
 import 'package:meta/meta.dart';
 
 import 'channel.dart' as channel;
 import 'options.dart';
-import 'transport/transport.dart';
 import 'transport/http2_transport.dart';
+import 'transport/transport.dart';
 
 @visibleForTesting
 Future<Transport> connectTransport(
diff --git a/lib/src/client/options.dart b/lib/src/client/options.dart
index fb8c651..7974798 100644
--- a/lib/src/client/options.dart
+++ b/lib/src/client/options.dart
@@ -14,10 +14,10 @@
 // limitations under the License.
 
 import 'dart:async';
-import 'package:meta/meta.dart';
-
 import 'dart:math';
 
+import 'package:meta/meta.dart';
+
 const defaultIdleTimeout = const Duration(minutes: 5);
 
 typedef Duration BackoffStrategy(Duration lastBackoff);
diff --git a/lib/src/client/web_channel.dart b/lib/src/client/web_channel.dart
index 4db6c62..bf50557 100644
--- a/lib/src/client/web_channel.dart
+++ b/lib/src/client/web_channel.dart
@@ -13,6 +13,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+import 'dart:async';
+
 import 'package:grpc/src/client/options.dart';
 import 'package:grpc/src/client/transport/transport.dart';
 import 'package:grpc/src/client/transport/xhr_transport.dart';
diff --git a/lib/src/shared/message.dart b/lib/src/shared/message.dart
index 1abb6ea..73e0f1d 100644
--- a/lib/src/shared/message.dart
+++ b/lib/src/shared/message.dart
@@ -1,3 +1,18 @@
+// Copyright (c) 2019, the gRPC project authors. Please see the AUTHORS file
+// for details. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 import 'dart:async';
 import 'dart:typed_data';
 
diff --git a/lib/src/shared/streams.dart b/lib/src/shared/streams.dart
index 2e78245..68c9ead 100644
--- a/lib/src/shared/streams.dart
+++ b/lib/src/shared/streams.dart
@@ -13,7 +13,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import 'dart:async';
 import 'dart:convert';
 import 'dart:math';
 import 'dart:typed_data';