Merge pull request #1646 from jtattermusch/csharp_api_fixes

Incorporate feedback from API review: Use IAsyncEnumerator to represent async read stream

26 files changed, 116 insertions, 129 deletions

diff --git a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
index eac8d16fb1..62cb443272 100644
--- a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
+++ b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
@@ -34,6 +34,9 @@
       <HintPath>..\packages\NUnit.2.6.4\lib\nunit.framework.dll</HintPath>
     </Reference>
     <Reference Include="System" />
+    <Reference Include="System.Interactive.Async">
+      <HintPath>..\packages\Ix-Async.1.2.3\lib\net45\System.Interactive.Async.dll</HintPath>
+    </Reference>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Properties\AssemblyInfo.cs" />
@@ -57,7 +60,5 @@
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
   </ItemGroup>
-  <ItemGroup>
-    <Folder Include="Internal\" />
-  </ItemGroup>
+  <ItemGroup />
 </Project>
\ No newline at end of file
diff --git a/src/csharp/Grpc.Core.Tests/packages.config b/src/csharp/Grpc.Core.Tests/packages.config
index c714ef3a23..28af8d78c6 100644
--- a/src/csharp/Grpc.Core.Tests/packages.config
+++ b/src/csharp/Grpc.Core.Tests/packages.config
@@ -1,4 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
+  <package id="Ix-Async" version="1.2.3" targetFramework="net45" />
   <package id="NUnit" version="2.6.4" targetFramework="net45" />
 </packages>
\ No newline at end of file
diff --git a/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs b/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
index b95776f66d..8cdc1c895b 100644
--- a/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
@@ -41,8 +41,6 @@ namespace Grpc.Core
     /// Return type for client streaming calls.
     /// </summary>
     public sealed class AsyncClientStreamingCall<TRequest, TResponse>
-        where TRequest : class
-        where TResponse : class
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly Task<TResponse> result;
@@ -54,22 +52,6 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Writes a request to RequestStream.
-        /// </summary>
-        public Task Write(TRequest message)
-        {
-            return requestStream.Write(message);
-        }
-
-        /// <summary>
-        /// Closes the RequestStream.
-        /// </summary>
-        public Task Close()
-        {
-            return requestStream.Close();
-        }
-
-        /// <summary>
         /// Asynchronous call result.
         /// </summary>
         public Task<TResponse> Result
diff --git a/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs b/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
index ee05437416..0d13a3d052 100644
--- a/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
@@ -41,8 +41,6 @@ namespace Grpc.Core
     /// Return type for bidirectional streaming calls.
     /// </summary>
     public sealed class AsyncDuplexStreamingCall<TRequest, TResponse>
-        where TRequest : class
-        where TResponse : class
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly IAsyncStreamReader<TResponse> responseStream;
@@ -54,31 +52,6 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Writes a request to RequestStream.
-        /// </summary>
-        public Task Write(TRequest message)
-        {
-            return requestStream.Write(message);
-        }
-
-        /// <summary>
-        /// Closes the RequestStream.
-        /// </summary>
-        public Task Close()
-        {
-            return requestStream.Close();
-        }
-
-        /// <summary>
-        /// Reads a response from ResponseStream.
-        /// </summary>
-        /// <returns></returns>
-        public Task<TResponse> ReadNext()
-        {
-            return responseStream.ReadNext();
-        }
-
-        /// <summary>
         /// Async stream to read streaming responses.
         /// </summary>
         public IAsyncStreamReader<TResponse> ResponseStream
diff --git a/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs b/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
index 73b9614985..6a258d132c 100644
--- a/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
@@ -41,7 +41,6 @@ namespace Grpc.Core
     /// Return type for server streaming calls.
     /// </summary>
     public sealed class AsyncServerStreamingCall<TResponse>
-        where TResponse : class
     {
         readonly IAsyncStreamReader<TResponse> responseStream;
 
@@ -51,15 +50,6 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Reads the next response from ResponseStream
-        /// </summary>
-        /// <returns></returns>
-        public Task<TResponse> ReadNext()
-        {
-            return responseStream.ReadNext();
-        }
-
-        /// <summary>
         /// Async stream to read streaming responses.
         /// </summary>
         public IAsyncStreamReader<TResponse> ResponseStream
diff --git a/src/csharp/Grpc.Core/Call.cs b/src/csharp/Grpc.Core/Call.cs
index d1ee59ff0a..37b452f020 100644
--- a/src/csharp/Grpc.Core/Call.cs
+++ b/src/csharp/Grpc.Core/Call.cs
@@ -41,8 +41,6 @@ namespace Grpc.Core
     /// Abstraction of a call to be invoked on a client.
     /// </summary>
     public class Call<TRequest, TResponse>
-        where TRequest : class
-        where TResponse : class
     {
         readonly string name;
         readonly Marshaller<TRequest> requestMarshaller;
diff --git a/src/csharp/Grpc.Core/Grpc.Core.csproj b/src/csharp/Grpc.Core/Grpc.Core.csproj
index f5f2cf5f22..6b4345cbe1 100644
--- a/src/csharp/Grpc.Core/Grpc.Core.csproj
+++ b/src/csharp/Grpc.Core/Grpc.Core.csproj
@@ -37,6 +37,9 @@
     <Reference Include="System.Collections.Immutable">
       <HintPath>..\packages\Microsoft.Bcl.Immutable.1.0.34\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
     </Reference>
+    <Reference Include="System.Interactive.Async">
+      <HintPath>..\packages\Ix-Async.1.2.3\lib\net45\System.Interactive.Async.dll</HintPath>
+    </Reference>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="AsyncDuplexStreamingCall.cs" />
diff --git a/src/csharp/Grpc.Core/Grpc.Core.nuspec b/src/csharp/Grpc.Core/Grpc.Core.nuspec
index e54908cb8b..5269881afa 100644
--- a/src/csharp/Grpc.Core/Grpc.Core.nuspec
+++ b/src/csharp/Grpc.Core/Grpc.Core.nuspec
@@ -16,6 +16,7 @@
     <tags>gRPC RPC Protocol HTTP/2</tags>
 	<dependencies>
 	  <dependency id="Microsoft.Bcl.Immutable" version="1.0.34" />
+	  <dependency id="Ix-Async" version="1.2.3" />
 	  <dependency id="grpc.native.csharp_ext" version="0.8.0.0" />
     </dependencies>
   </metadata>
diff --git a/src/csharp/Grpc.Core/IAsyncStreamReader.cs b/src/csharp/Grpc.Core/IAsyncStreamReader.cs
index 699741cd05..95b674c018 100644
--- a/src/csharp/Grpc.Core/IAsyncStreamReader.cs
+++ b/src/csharp/Grpc.Core/IAsyncStreamReader.cs
@@ -43,13 +43,7 @@ namespace Grpc.Core
     /// A stream of messages to be read.
     /// </summary>
     /// <typeparam name="T"></typeparam>
-    public interface IAsyncStreamReader<T>
-        where T : class
+    public interface IAsyncStreamReader<TResponse> : IAsyncEnumerator<TResponse>
     {
-        /// <summary>
-        /// Reads a single message. Returns null if the last message was already read.
-        /// A following read can only be started when the previous one finishes.
-        /// </summary>
-        Task<T> ReadNext();
     }
 }
diff --git a/src/csharp/Grpc.Core/IAsyncStreamWriter.cs b/src/csharp/Grpc.Core/IAsyncStreamWriter.cs
index 4bd8bfb8df..644f445401 100644
--- a/src/csharp/Grpc.Core/IAsyncStreamWriter.cs
+++ b/src/csharp/Grpc.Core/IAsyncStreamWriter.cs
@@ -44,10 +44,9 @@ namespace Grpc.Core
     /// </summary>
     /// <typeparam name="T"></typeparam>
     public interface IAsyncStreamWriter<T>
-        where T : class
     {
         /// <summary>
-        /// Writes a single message. Only one write can be pending at a time.
+        /// Writes a single asynchronously. Only one write can be pending at a time.
         /// </summary>
         /// <param name="message">the message to be written. Cannot be null.</param>
         Task Write(T message);
diff --git a/src/csharp/Grpc.Core/IClientStreamWriter.cs b/src/csharp/Grpc.Core/IClientStreamWriter.cs
index 0847a928e6..cc76d1369d 100644
--- a/src/csharp/Grpc.Core/IClientStreamWriter.cs
+++ b/src/csharp/Grpc.Core/IClientStreamWriter.cs
@@ -44,11 +44,10 @@ namespace Grpc.Core
     /// </summary>
     /// <typeparam name="T"></typeparam>
     public interface IClientStreamWriter<T> : IAsyncStreamWriter<T>
-        where T : class
     {
         /// <summary>
-        /// Closes the stream. Can only be called once there is no pending write. No writes should follow calling this.
+        /// Completes/closes the stream. Can only be called once there is no pending write. No writes should follow calling this.
         /// </summary>
-        Task Close();
+        Task Complete();
     }
 }
diff --git a/src/csharp/Grpc.Core/Internal/ClientRequestStream.cs b/src/csharp/Grpc.Core/Internal/ClientRequestStream.cs
index 1697058732..b9fc10cd16 100644
--- a/src/csharp/Grpc.Core/Internal/ClientRequestStream.cs
+++ b/src/csharp/Grpc.Core/Internal/ClientRequestStream.cs
@@ -38,8 +38,6 @@ namespace Grpc.Core.Internal
     /// Writes requests asynchronously to an underlying AsyncCall object.
     /// </summary>
     internal class ClientRequestStream<TRequest, TResponse> : IClientStreamWriter<TRequest>
-        where TRequest : class
-        where TResponse : class
     {
         readonly AsyncCall<TRequest, TResponse> call;
 
@@ -55,7 +53,7 @@ namespace Grpc.Core.Internal
             return taskSource.Task;
         }
 
-        public Task Close()
+        public Task Complete()
         {
             var taskSource = new AsyncCompletionTaskSource<object>();
             call.StartSendCloseFromClient(taskSource.CompletionDelegate);
diff --git a/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs b/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
index b2378cade6..6c44521038 100644
--- a/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
+++ b/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
@@ -33,6 +33,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Grpc.Core.Internal
@@ -42,17 +43,41 @@ namespace Grpc.Core.Internal
         where TResponse : class
     {
         readonly AsyncCall<TRequest, TResponse> call;
+        TResponse current;
 
         public ClientResponseStream(AsyncCall<TRequest, TResponse> call)
         {
             this.call = call;
         }
 
-        public Task<TResponse> ReadNext()
+        public TResponse Current
         {
+            get
+            {
+                if (current == null)
+                {
+                    throw new InvalidOperationException("No current element is available.");
+                }
+                return current;
+            }
+        }
+
+        public async Task<bool> MoveNext(CancellationToken token)
+        {
+            if (token != CancellationToken.None)
+            {
+                throw new InvalidOperationException("Cancellation of individual reads is not supported.");
+            }
             var taskSource = new AsyncCompletionTaskSource<TResponse>();
             call.StartReadMessage(taskSource.CompletionDelegate);
-            return taskSource.Task;
+            var result = await taskSource.Task;
+            this.current = result;
+            return result != null;
+        }
+
+        public void Dispose()
+        {
+            // TODO(jtattermusch): implement the semantics of stream disposal.
         }
     }
 }
diff --git a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
index 95d8e97869..20ac46c234 100644
--- a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
@@ -32,6 +32,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using Grpc.Core.Internal;
@@ -71,9 +72,10 @@ namespace Grpc.Core.Internal
             Status status = Status.DefaultSuccess;
             try
             {
-                var request = await requestStream.ReadNext();
+                Preconditions.CheckArgument(await requestStream.MoveNext());
+                var request = requestStream.Current;
                 // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
-                Preconditions.CheckArgument(await requestStream.ReadNext() == null);
+                Preconditions.CheckArgument(!await requestStream.MoveNext());
                 var context = new ServerCallContext();  // TODO(jtattermusch): initialize the context
                 var result = await handler(context, request);
                 await responseStream.Write(result);
@@ -122,9 +124,10 @@ namespace Grpc.Core.Internal
             Status status = Status.DefaultSuccess;
             try
             {
-                var request = await requestStream.ReadNext();
+                Preconditions.CheckArgument(await requestStream.MoveNext());
+                var request = requestStream.Current;
                 // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
-                Preconditions.CheckArgument(await requestStream.ReadNext() == null);
+                Preconditions.CheckArgument(!await requestStream.MoveNext());
 
                 var context = new ServerCallContext();  // TODO(jtattermusch): initialize the context
                 await handler(context, request, responseStream);
diff --git a/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs b/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs
index d9ee0c815b..3fccb88abb 100644
--- a/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs
@@ -33,6 +33,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Grpc.Core.Internal
@@ -42,17 +43,41 @@ namespace Grpc.Core.Internal
         where TResponse : class
     {
         readonly AsyncCallServer<TRequest, TResponse> call;
+        TRequest current;
 
         public ServerRequestStream(AsyncCallServer<TRequest, TResponse> call)
         {
             this.call = call;
         }
 
-        public Task<TRequest> ReadNext()
+        public TRequest Current
         {
+            get
+            {
+                if (current == null)
+                {
+                    throw new InvalidOperationException("No current element is available.");
+                }
+                return current;
+            }
+        }
+
+        public async Task<bool> MoveNext(CancellationToken token)
+        {
+            if (token != CancellationToken.None)
+            {
+                throw new InvalidOperationException("Cancellation of individual reads is not supported.");
+            }
             var taskSource = new AsyncCompletionTaskSource<TRequest>();
             call.StartReadMessage(taskSource.CompletionDelegate);
-            return taskSource.Task;
+            var result = await taskSource.Task;
+            this.current = result;
+            return result != null;
+        }
+
+        public void Dispose()
+        {
+            // TODO(jtattermusch): implement the semantics of stream disposal.
         }
     }
 }
diff --git a/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs b/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs
index 731ea2be81..7a1c016ae2 100644
--- a/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs
@@ -39,9 +39,6 @@ using Grpc.Core.Utils;
 
 namespace Grpc.Core.Internal
 {
-    // TODO: we need to make sure that the delegates are not collected before invoked.
-    //internal delegate void ServerShutdownCallbackDelegate(bool success);
-
     /// <summary>
     /// grpc_server from grpc/grpc.h
     /// </summary>
diff --git a/src/csharp/Grpc.Core/ServerCallContext.cs b/src/csharp/Grpc.Core/ServerCallContext.cs
index e873b3e88a..bc9a499c51 100644
--- a/src/csharp/Grpc.Core/ServerCallContext.cs
+++ b/src/csharp/Grpc.Core/ServerCallContext.cs
@@ -42,7 +42,6 @@ namespace Grpc.Core
     /// </summary>
     public sealed class ServerCallContext
     {
-        
         // TODO(jtattermusch): add cancellationToken
 
         // TODO(jtattermusch): add deadline info
diff --git a/src/csharp/Grpc.Core/Utils/AsyncStreamExtensions.cs b/src/csharp/Grpc.Core/Utils/AsyncStreamExtensions.cs
index f915155f8a..a4f8989b30 100644
--- a/src/csharp/Grpc.Core/Utils/AsyncStreamExtensions.cs
+++ b/src/csharp/Grpc.Core/Utils/AsyncStreamExtensions.cs
@@ -49,14 +49,9 @@ namespace Grpc.Core.Utils
         public static async Task ForEach<T>(this IAsyncStreamReader<T> streamReader, Func<T, Task> asyncAction)
             where T : class
         {
-            while (true)
+            while (await streamReader.MoveNext())
             {
-                var elem = await streamReader.ReadNext();
-                if (elem == null)
-                {
-                    break;
-                }
-                await asyncAction(elem);
+                await asyncAction(streamReader.Current);
             }
         }
 
@@ -67,32 +62,27 @@ namespace Grpc.Core.Utils
             where T : class
         {
             var result = new List<T>();
-            while (true)
+            while (await streamReader.MoveNext())
             {
-                var elem = await streamReader.ReadNext();
-                if (elem == null)
-                {
-                    break;
-                }
-                result.Add(elem);
+                result.Add(streamReader.Current);
             }
             return result;
         }
 
         /// <summary>
         /// Writes all elements from given enumerable to the stream.
-        /// Closes the stream afterwards unless close = false.
+        /// Completes the stream afterwards unless close = false.
         /// </summary>
-        public static async Task WriteAll<T>(this IClientStreamWriter<T> streamWriter, IEnumerable<T> elements, bool close = true)
+        public static async Task WriteAll<T>(this IClientStreamWriter<T> streamWriter, IEnumerable<T> elements, bool complete = true)
             where T : class
         {
             foreach (var element in elements)
             {
                 await streamWriter.Write(element);
             }
-            if (close)
+            if (complete)
             {
-                await streamWriter.Close();
+                await streamWriter.Complete();
             }
         }
 
diff --git a/src/csharp/Grpc.Core/packages.config b/src/csharp/Grpc.Core/packages.config
index 71967de56e..fb7eaaeeda 100644
--- a/src/csharp/Grpc.Core/packages.config
+++ b/src/csharp/Grpc.Core/packages.config
@@ -2,5 +2,6 @@
 <packages>
   <package id="grpc.dependencies.openssl.redist" version="1.0.2.2" targetFramework="net45" />
   <package id="grpc.dependencies.zlib.redist" version="1.2.8.9" targetFramework="net45" />
+  <package id="Ix-Async" version="1.2.3" targetFramework="net45" />
   <package id="Microsoft.Bcl.Immutable" version="1.0.34" targetFramework="net45" />
 </packages>
\ No newline at end of file
diff --git a/src/csharp/Grpc.Examples.Tests/Grpc.Examples.Tests.csproj b/src/csharp/Grpc.Examples.Tests/Grpc.Examples.Tests.csproj
index 87ccf07dd8..6e84add42b 100644
--- a/src/csharp/Grpc.Examples.Tests/Grpc.Examples.Tests.csproj
+++ b/src/csharp/Grpc.Examples.Tests/Grpc.Examples.Tests.csproj
@@ -37,6 +37,10 @@
     <Reference Include="Google.ProtocolBuffers">
       <HintPath>..\packages\Google.ProtocolBuffers.2.4.1.521\lib\net40\Google.ProtocolBuffers.dll</HintPath>
     </Reference>
+    <Reference Include="System.Interactive.Async, Version=1.2.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
+      <HintPath>..\packages\Ix-Async.1.2.3\lib\net45\System.Interactive.Async.dll</HintPath>
+    </Reference>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Properties\AssemblyInfo.cs" />
diff --git a/src/csharp/Grpc.Examples.Tests/packages.config b/src/csharp/Grpc.Examples.Tests/packages.config
index 4d6ec63b3c..cc6e9af40f 100644
--- a/src/csharp/Grpc.Examples.Tests/packages.config
+++ b/src/csharp/Grpc.Examples.Tests/packages.config
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>

 <packages>

   <package id="Google.ProtocolBuffers" version="2.4.1.521" targetFramework="net45" />

+  <package id="Ix-Async" version="1.2.3" targetFramework="net45" />

   <package id="NUnit" version="2.6.4" targetFramework="net45" />

 </packages>
\ No newline at end of file
diff --git a/src/csharp/Grpc.Examples/Grpc.Examples.csproj b/src/csharp/Grpc.Examples/Grpc.Examples.csproj
index 2c5019c214..5ce490f403 100644
--- a/src/csharp/Grpc.Examples/Grpc.Examples.csproj
+++ b/src/csharp/Grpc.Examples/Grpc.Examples.csproj
@@ -35,6 +35,9 @@
     <Reference Include="Google.ProtocolBuffers">
       <HintPath>..\packages\Google.ProtocolBuffers.2.4.1.521\lib\net40\Google.ProtocolBuffers.dll</HintPath>
     </Reference>
+    <Reference Include="System.Interactive.Async">
+      <HintPath>..\packages\Ix-Async.1.2.3\lib\net45\System.Interactive.Async.dll</HintPath>
+    </Reference>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Properties\AssemblyInfo.cs" />
diff --git a/src/csharp/Grpc.Examples/packages.config b/src/csharp/Grpc.Examples/packages.config
index 51c17bcd5e..4c8d60fa62 100644
--- a/src/csharp/Grpc.Examples/packages.config
+++ b/src/csharp/Grpc.Examples/packages.config
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="Google.ProtocolBuffers" version="2.4.1.521" targetFramework="net45" />
+  <package id="Ix-Async" version="1.2.3" targetFramework="net45" />
   <package id="NUnit" version="2.6.4" targetFramework="net45" />
 </packages>
\ No newline at end of file
diff --git a/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj b/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
index 1ca3dd24e1..b3a0a2917b 100644
--- a/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
+++ b/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
@@ -54,6 +54,9 @@
     <Reference Include="Google.ProtocolBuffers">
       <HintPath>..\packages\Google.ProtocolBuffers.2.4.1.521\lib\net40\Google.ProtocolBuffers.dll</HintPath>
     </Reference>
+    <Reference Include="System.Interactive.Async">
+      <HintPath>..\packages\Ix-Async.1.2.3\lib\net45\System.Interactive.Async.dll</HintPath>
+    </Reference>
     <Reference Include="System.Net" />
     <Reference Include="System.Net.Http" />
     <Reference Include="System.Net.Http.Extensions">
diff --git a/src/csharp/Grpc.IntegrationTesting/InteropClient.cs b/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
index 02f8a369de..d907699698 100644
--- a/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
+++ b/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
@@ -256,48 +256,45 @@ namespace Grpc.IntegrationTesting
 
                 var call = client.FullDuplexCall();
 
-                StreamingOutputCallResponse response;
-
                 await call.RequestStream.Write(StreamingOutputCallRequest.CreateBuilder()
                 .SetResponseType(PayloadType.COMPRESSABLE)
                 .AddResponseParameters(ResponseParameters.CreateBuilder().SetSize(31415))
                 .SetPayload(CreateZerosPayload(27182)).Build());
 
-                response = await call.ResponseStream.ReadNext();
-                Assert.AreEqual(PayloadType.COMPRESSABLE, response.Payload.Type);
-                Assert.AreEqual(31415, response.Payload.Body.Length);
+                Assert.IsTrue(await call.ResponseStream.MoveNext());
+                Assert.AreEqual(PayloadType.COMPRESSABLE, call.ResponseStream.Current.Payload.Type);
+                Assert.AreEqual(31415, call.ResponseStream.Current.Payload.Body.Length);
 
                 await call.RequestStream.Write(StreamingOutputCallRequest.CreateBuilder()
                           .SetResponseType(PayloadType.COMPRESSABLE)
                           .AddResponseParameters(ResponseParameters.CreateBuilder().SetSize(9))
                           .SetPayload(CreateZerosPayload(8)).Build());
 
-                response = await call.ResponseStream.ReadNext();
-                Assert.AreEqual(PayloadType.COMPRESSABLE, response.Payload.Type);
-                Assert.AreEqual(9, response.Payload.Body.Length);
+                Assert.IsTrue(await call.ResponseStream.MoveNext());
+                Assert.AreEqual(PayloadType.COMPRESSABLE, call.ResponseStream.Current.Payload.Type);
+                Assert.AreEqual(9, call.ResponseStream.Current.Payload.Body.Length);
 
                 await call.RequestStream.Write(StreamingOutputCallRequest.CreateBuilder()
                           .SetResponseType(PayloadType.COMPRESSABLE)
                           .AddResponseParameters(ResponseParameters.CreateBuilder().SetSize(2653))
                           .SetPayload(CreateZerosPayload(1828)).Build());
 
-                response = await call.ResponseStream.ReadNext();
-                Assert.AreEqual(PayloadType.COMPRESSABLE, response.Payload.Type);
-                Assert.AreEqual(2653, response.Payload.Body.Length);
+                Assert.IsTrue(await call.ResponseStream.MoveNext());
+                Assert.AreEqual(PayloadType.COMPRESSABLE, call.ResponseStream.Current.Payload.Type);
+                Assert.AreEqual(2653, call.ResponseStream.Current.Payload.Body.Length);
 
                 await call.RequestStream.Write(StreamingOutputCallRequest.CreateBuilder()
                           .SetResponseType(PayloadType.COMPRESSABLE)
                           .AddResponseParameters(ResponseParameters.CreateBuilder().SetSize(58979))
                           .SetPayload(CreateZerosPayload(45904)).Build());
 
-                response = await call.ResponseStream.ReadNext();
-                Assert.AreEqual(PayloadType.COMPRESSABLE, response.Payload.Type);
-                Assert.AreEqual(58979, response.Payload.Body.Length);
+                Assert.IsTrue(await call.ResponseStream.MoveNext());
+                Assert.AreEqual(PayloadType.COMPRESSABLE, call.ResponseStream.Current.Payload.Type);
+                Assert.AreEqual(58979, call.ResponseStream.Current.Payload.Body.Length);
 
-                await call.RequestStream.Close();
+                await call.RequestStream.Complete();
 
-                response = await call.ResponseStream.ReadNext();
-                Assert.AreEqual(null, response);
+                Assert.IsFalse(await call.ResponseStream.MoveNext());
 
                 Console.WriteLine("Passed!");
             }).Wait();
@@ -309,7 +306,7 @@ namespace Grpc.IntegrationTesting
             {
                 Console.WriteLine("running empty_stream");
                 var call = client.FullDuplexCall();
-                await call.Close();
+                await call.RequestStream.Complete();
 
                 var responseList = await call.ResponseStream.ToList();
                 Assert.AreEqual(0, responseList.Count);
@@ -392,22 +389,20 @@ namespace Grpc.IntegrationTesting
                 var cts = new CancellationTokenSource();
                 var call = client.FullDuplexCall(cts.Token);
 
-                StreamingOutputCallResponse response;
-
                 await call.RequestStream.Write(StreamingOutputCallRequest.CreateBuilder()
                     .SetResponseType(PayloadType.COMPRESSABLE)
                     .AddResponseParameters(ResponseParameters.CreateBuilder().SetSize(31415))
                     .SetPayload(CreateZerosPayload(27182)).Build());
 
-                response = await call.ResponseStream.ReadNext();
-                Assert.AreEqual(PayloadType.COMPRESSABLE, response.Payload.Type);
-                Assert.AreEqual(31415, response.Payload.Body.Length);
+                Assert.IsTrue(await call.ResponseStream.MoveNext());
+                Assert.AreEqual(PayloadType.COMPRESSABLE, call.ResponseStream.Current.Payload.Type);
+                Assert.AreEqual(31415, call.ResponseStream.Current.Payload.Body.Length);
 
                 cts.Cancel();
 
                 try
                 {
-                    response = await call.ResponseStream.ReadNext();
+                    await call.ResponseStream.MoveNext();
                     Assert.Fail();
                 }
                 catch (RpcException e)
diff --git a/src/csharp/Grpc.IntegrationTesting/packages.config b/src/csharp/Grpc.IntegrationTesting/packages.config
index e33b6e3e46..291b7b8599 100644
--- a/src/csharp/Grpc.IntegrationTesting/packages.config
+++ b/src/csharp/Grpc.IntegrationTesting/packages.config
@@ -3,6 +3,7 @@
   <package id="Google.Apis.Auth" version="1.9.1" targetFramework="net45" />
   <package id="Google.Apis.Core" version="1.9.1" targetFramework="net45" />
   <package id="Google.ProtocolBuffers" version="2.4.1.521" targetFramework="net45" />
+  <package id="Ix-Async" version="1.2.3" targetFramework="net45" />
   <package id="Microsoft.Bcl" version="1.1.9" targetFramework="net45" />
   <package id="Microsoft.Bcl.Async" version="1.0.168" targetFramework="net45" />
   <package id="Microsoft.Bcl.Build" version="1.0.14" targetFramework="net45" />