diff --git a/examples/transaction.rs b/examples/transaction.rs
index 3d258fa..72aaf7a 100644
--- a/examples/transaction.rs
+++ b/examples/transaction.rs
@@ -5,11 +5,7 @@
 mod common;
 
 use crate::common::parse_args;
-use futures::{
-    future,
-    prelude::{StreamExt, TryStreamExt},
-    stream, TryFutureExt,
-};
+use futures::prelude::*;
 use std::ops::RangeBounds;
 use tikv_client::{
     transaction::{Client, IsolationLevel},
diff --git a/src/compat.rs b/src/compat.rs
index 1b4e2ae..e7b3d09 100644
--- a/src/compat.rs
+++ b/src/compat.rs
@@ -3,8 +3,7 @@
 //! This module contains utility types and functions for making the transition
 //! from futures 0.1 to 1.0 easier.
 
-use futures::prelude::{Future, Sink, Stream, StreamExt};
-use futures::stream::Fuse;
+use futures::prelude::*;
 use futures::task::{Context, Poll};
 use futures::try_ready;
 use std::pin::Pin;
@@ -85,7 +84,7 @@ where
     St: Stream + Unpin,
 {
     sink: Option<Si>,
-    stream: Option<Fuse<St>>,
+    stream: Option<stream::Fuse<St>>,
     buffered: Option<St::Item>,
 }
 
@@ -118,7 +117,7 @@ where
         )
     }
 
-    fn stream_mut(&mut self) -> Pin<&mut Fuse<St>> {
+    fn stream_mut(&mut self) -> Pin<&mut stream::Fuse<St>> {
         Pin::new(
             self.stream
                 .as_mut()
diff --git a/src/raw.rs b/src/raw.rs
index 9806249..e7c06f7 100644
--- a/src/raw.rs
+++ b/src/raw.rs
@@ -10,7 +10,8 @@
 //! **Warning:** It is not advisable to use both raw and transactional functionality in the same keyspace.
 //!
 use crate::{rpc::RpcClient, Config, Error, Key, KeyRange, KvPair, Result, Value};
-use futures::{future, task::Context, Future, Poll};
+use futures::prelude::*;
+use futures::task::{Context, Poll};
 use std::{fmt, ops::Bound, pin::Pin, sync::Arc, u32};
 
 const MAX_RAW_KV_SCAN_LIMIT: u32 = 10240;
diff --git a/src/rpc/client.rs b/src/rpc/client.rs
index 73ae8ca..686d433 100644
--- a/src/rpc/client.rs
+++ b/src/rpc/client.rs
@@ -10,8 +10,7 @@ use std::{
     time::Duration,
 };
 
-use futures::future::{self, ready, Either, Future};
-use futures::prelude::TryFutureExt;
+use futures::prelude::*;
 use grpcio::{EnvBuilder, Environment};
 use kvproto::kvrpcpb;
 use log::*;
@@ -153,33 +152,31 @@ impl RpcClient {
         let inner = self.inner();
         loop_fn((0, tasks, result), move |(mut index, tasks, mut result)| {
             if index == tasks.len() {
-                Either::Left(future::ok(Loop::Break(result)))
+                future::Either::Left(future::ok(Loop::Break(result)))
             } else {
                 let inner = Arc::clone(&inner);
-                Either::Right(
-                    inner
-                        .locate_key(tasks[index].key())
-                        .map_ok(move |location| {
-                            while let Some(item) = tasks.get(index) {
-                                if !location.contains(item.key()) {
-                                    break;
-                                }
-                                let ver_id = location.ver_id();
-                                let item = item.clone();
-                                if let Some(ref mut grouped) = result {
-                                    grouped.add(ver_id, item);
-                                } else {
-                                    result = Some(GroupedTasks::new(ver_id, item));
-                                }
-                                index += 1;
+                future::Either::Right(inner.locate_key(tasks[index].key()).map_ok(
+                    move |location| {
+                        while let Some(item) = tasks.get(index) {
+                            if !location.contains(item.key()) {
+                                break;
                             }
-                            if index == tasks.len() {
-                                Loop::Break(result)
+                            let ver_id = location.ver_id();
+                            let item = item.clone();
+                            if let Some(ref mut grouped) = result {
+                                grouped.add(ver_id, item);
                             } else {
-                                Loop::Continue((index, tasks, result))
+                                result = Some(GroupedTasks::new(ver_id, item));
                             }
-                        }),
-                )
+                            index += 1;
+                        }
+                        if index == tasks.len() {
+                            Loop::Break(result)
+                        } else {
+                            Loop::Continue((index, tasks, result))
+                        }
+                    },
+                ))
             }
         })
         .map_ok(|r| r.unwrap_or_default())
@@ -200,7 +197,7 @@ impl RpcClient {
                     store,
                 })
             })
-            .and_then(move |region| ready(inner2.kv_client(region)))
+            .and_then(move |region| future::ready(inner2.kv_client(region)))
     }
 
     fn region_context_by_id(
@@ -217,7 +214,7 @@ impl RpcClient {
                     .load_store(store_id)
                     .map_ok(|store| RegionContext { region, store })
             })
-            .and_then(move |region| ready(inner2.kv_client(region)))
+            .and_then(move |region| future::ready(inner2.kv_client(region)))
     }
 
     fn raw(
@@ -279,9 +276,9 @@ impl RpcClient {
         cf: Option<ColumnFamily>,
     ) -> impl Future<Output = Result<()>> {
         if value.is_empty() {
-            Either::Left(future::err(Error::empty_value()))
+            future::Either::Left(future::err(Error::empty_value()))
         } else {
-            Either::Right(
+            future::Either::Right(
                 Self::raw(self.inner(), &key, cf)
                     .and_then(|context| context.client().raw_put(context, key, value)),
             )
@@ -294,10 +291,10 @@ impl RpcClient {
         cf: Option<ColumnFamily>,
     ) -> impl Future<Output = Result<()>> {
         if pairs.iter().any(|p| p.value().is_empty()) {
-            Either::Left(future::err(Error::empty_value()))
+            future::Either::Left(future::err(Error::empty_value()))
         } else {
             let inner = self.inner();
-            Either::Right(
+            future::Either::Right(
                 self.group_tasks_by_region(pairs)
                     .and_then(move |task_groups| {
                         let mut tasks = Vec::with_capacity(task_groups.len());
diff --git a/src/rpc/pd/client.rs b/src/rpc/pd/client.rs
index cb4842a..737871c 100644
--- a/src/rpc/pd/client.rs
+++ b/src/rpc/pd/client.rs
@@ -7,8 +7,7 @@ use std::{
 };
 
 use futures::compat::Compat01As03;
-use futures::future::{ready, Future};
-use futures::prelude::{FutureExt, TryFutureExt};
+use futures::prelude::*;
 use grpcio::{CallOption, Environment};
 use kvproto::{metapb, pdpb, pdpb::PdClient as RpcClient};
 
@@ -93,14 +92,14 @@ impl PdClient {
             let region = if resp.has_region() {
                 resp.take_region()
             } else {
-                return ready(Err(Error::region_for_key_not_found(key)));
+                return future::ready(Err(Error::region_for_key_not_found(key)));
             };
             let leader = if resp.has_leader() {
                 Some(resp.take_leader())
             } else {
                 None
             };
-            ready(Ok((region, leader)))
+            future::ready(Ok((region, leader)))
         })
     }
 
@@ -122,14 +121,14 @@ impl PdClient {
             let region = if resp.has_region() {
                 resp.take_region()
             } else {
-                return ready(Err(Error::region_not_found(region_id, None)));
+                return future::ready(Err(Error::region_not_found(region_id, None)));
             };
             let leader = if resp.has_leader() {
                 Some(resp.take_leader())
             } else {
                 None
             };
-            ready(Ok((region, leader)))
+            future::ready(Ok((region, leader)))
         })
     }
 
diff --git a/src/rpc/pd/leader.rs b/src/rpc/pd/leader.rs
index 4778ad7..eaf2949 100644
--- a/src/rpc/pd/leader.rs
+++ b/src/rpc/pd/leader.rs
@@ -7,21 +7,16 @@ use std::{
     time::{Duration, Instant},
 };
 
-use futures::prelude::{FutureExt, SinkExt, StreamExt, TryFutureExt};
-use futures::{
-    channel::{
-        mpsc::{channel, unbounded, Receiver, Sender, UnboundedReceiver, UnboundedSender},
-        oneshot,
-    },
-    compat::{Compat01As03, Compat01As03Sink},
-    future::ready,
-    stream::TryStreamExt,
-    Future,
+use futures::channel::{
+    mpsc::{channel, unbounded, Receiver, Sender, UnboundedReceiver, UnboundedSender},
+    oneshot,
 };
+use futures::compat::{Compat01As03, Compat01As03Sink};
+use futures::prelude::*;
 use grpcio::{CallOption, Environment, WriteFlags};
 use kvproto::pdpb;
 use log::*;
-use tokio_core::reactor::{Core, Handle as OtherHandle};
+use tokio_core::reactor::{Core, Handle as TokioHandle};
 
 use crate::{
     compat::SinkCompat,
@@ -119,15 +114,15 @@ impl PdReactor {
         let mut core = Core::new().unwrap();
         let handle = core.handle();
         {
-            let f = rx.take_while(|t| ready(t.is_some())).for_each(|t| {
+            let f = rx.take_while(|t| future::ready(t.is_some())).for_each(|t| {
                 Self::dispatch(&client, t.unwrap(), &handle);
-                ready(())
+                future::ready(())
             });
             core.run(TryFutureExt::compat(f.unit_error())).unwrap();
         }
     }
 
-    fn init(client: &Arc<RwLock<LeaderClient>>, handle: &OtherHandle) {
+    fn init(client: &Arc<RwLock<LeaderClient>>, handle: &TokioHandle) {
         let client = Arc::clone(client);
         let (tx, rx) = client.write().unwrap().client.tso().unwrap();
         let tx = Compat01As03Sink::new(tx);
@@ -164,7 +159,7 @@ impl PdReactor {
                     // Schedule another tso_batch of request
                     reactor.schedule(PdTask::Request);
                 }
-                ready(Ok(()))
+                future::ready(Ok(()))
             })
             .map_err(|e| panic!("unexpected error: {:?}", e))
             .compat(),
@@ -204,7 +199,7 @@ impl PdReactor {
         client.write().unwrap().reactor.tso_buffer = Some(requests);
     }
 
-    fn dispatch(client: &Arc<RwLock<LeaderClient>>, task: PdTask, handle: &OtherHandle) {
+    fn dispatch(client: &Arc<RwLock<LeaderClient>>, task: PdTask, handle: &TokioHandle) {
         match task {
             PdTask::Request => Self::tso_request(client),
             PdTask::Response(requests, response) => Self::tso_response(client, requests, &response),
diff --git a/src/rpc/pd/request.rs b/src/rpc/pd/request.rs
index 0fe9575..68a2e43 100644
--- a/src/rpc/pd/request.rs
+++ b/src/rpc/pd/request.rs
@@ -7,8 +7,7 @@ use std::{
 };
 
 use futures::compat::Compat01As03;
-use futures::future::{ok, ready, Either, Future, TryFutureExt};
-use futures::prelude::FutureExt;
+use futures::prelude::*;
 use log::*;
 use tokio_timer::timer::Handle;
 
@@ -61,7 +60,7 @@ where
         debug!("reconnect remains: {}", self.reconnect_count);
 
         if self.request_sent < MAX_REQUEST_COUNT {
-            return Either::Left(ok(self));
+            return future::Either::Left(future::ok(self));
         }
 
         // Updating client.
@@ -71,9 +70,9 @@ where
         match (self.reconnect)(&self.client, RECONNECT_INTERVAL_SEC) {
             Ok(_) => {
                 self.request_sent = 0;
-                Either::Left(ok(self))
+                future::Either::Left(future::ok(self))
             }
-            Err(_) => Either::Right(
+            Err(_) => future::Either::Right(
                 Compat01As03::new(
                     self.timer
                         .delay(Instant::now() + Duration::from_secs(RECONNECT_INTERVAL_SEC)),
@@ -87,7 +86,7 @@ where
         self.request_sent += 1;
         debug!("request sent: {}", self.request_sent);
 
-        ok(self).and_then(|mut ctx| {
+        future::ok(self).and_then(|mut ctx| {
             let req = (ctx.func)(&ctx.client);
             req.map(|resp| match resp {
                 Ok(resp) => {
@@ -128,6 +127,6 @@ where
                 .and_then(Self::send_and_receive)
                 .map(Self::break_or_continue)
         })
-        .and_then(|r| ready(r.post_loop()))
+        .and_then(|r| future::ready(r.post_loop()))
     }
 }
diff --git a/src/rpc/tikv/client.rs b/src/rpc/tikv/client.rs
index 49b1ea7..e3f4fc1 100644
--- a/src/rpc/tikv/client.rs
+++ b/src/rpc/tikv/client.rs
@@ -6,8 +6,7 @@
 use std::{fmt, sync::Arc, time::Duration};
 
 use futures::compat::Compat01As03;
-use futures::future::Future;
-use futures::prelude::{FutureExt, TryFutureExt};
+use futures::prelude::*;
 use grpcio::{CallOption, Environment};
 use kvproto::{errorpb, kvrpcpb, tikvpb::TikvClient};
 
diff --git a/src/transaction.rs b/src/transaction.rs
index c5ab9e7..1d0c986 100644
--- a/src/transaction.rs
+++ b/src/transaction.rs
@@ -10,7 +10,9 @@
 //!
 
 use crate::{Config, Error, Key, KvPair, Value};
-use futures::{task::Context, Future, Poll, Stream};
+
+use futures::prelude::*;
+use futures::task::{Context, Poll};
 use std::ops::RangeBounds;
 use std::pin::Pin;