1 files changed, 34 insertions, 8 deletions
diff --git a/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs b/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
index 271a6ffadf..11acb27533 100644
--- a/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
+++ b/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
@@ -31,7 +31,7 @@ namespace Grpc.Core.Internal
     /// <summary>
     /// Manages server side native call lifecycle.
     /// </summary>
-    internal class AsyncCallServer<TRequest, TResponse> : AsyncCallBase<TResponse, TRequest>
+    internal class AsyncCallServer<TRequest, TResponse> : AsyncCallBase<TResponse, TRequest>, IReceivedCloseOnServerCallback, ISendStatusFromServerCompletionCallback
     {
         readonly TaskCompletionSource<object> finishedServersideTcs = new TaskCompletionSource<object>();
         readonly CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
@@ -70,7 +70,7 @@ namespace Grpc.Core.Internal
 
                 started = true;
 
-                call.StartServerSide(HandleFinishedServerside);
+                call.StartServerSide(ReceiveCloseOnServerCallback);
                 return finishedServersideTcs.Task;
             }
         }
@@ -114,7 +114,7 @@ namespace Grpc.Core.Internal
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(headers))
                 {
-                    call.StartSendInitialMetadata(HandleSendFinished, metadataArray);
+                    call.StartSendInitialMetadata(SendCompletionCallback, metadataArray);
                 }
 
                 this.initialMetadataSent = true;
@@ -127,10 +127,10 @@ namespace Grpc.Core.Internal
         /// Sends call result status, indicating we are done with writes.
         /// Sending a status different from StatusCode.OK will also implicitly cancel the call.
         /// </summary>
-        public Task SendStatusFromServerAsync(Status status, Metadata trailers, Tuple<TResponse, WriteFlags> optionalWrite)
+        public Task SendStatusFromServerAsync(Status status, Metadata trailers, ResponseWithFlags? optionalWrite)
         {
-            byte[] payload = optionalWrite != null ? UnsafeSerialize(optionalWrite.Item1) : null;
-            var writeFlags = optionalWrite != null ? optionalWrite.Item2 : default(WriteFlags);
+            byte[] payload = optionalWrite.HasValue ? UnsafeSerialize(optionalWrite.Value.Response) : null;
+            var writeFlags = optionalWrite.HasValue ? optionalWrite.Value.WriteFlags : default(WriteFlags);
 
             lock (myLock)
             {
@@ -140,13 +140,13 @@ namespace Grpc.Core.Internal
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(trailers))
                 {
-                    call.StartSendStatusFromServer(HandleSendStatusFromServerFinished, status, metadataArray, !initialMetadataSent,
+                    call.StartSendStatusFromServer(SendStatusFromServerCompletionCallback, status, metadataArray, !initialMetadataSent,
                         payload, writeFlags);
                 }
                 halfcloseRequested = true;
                 initialMetadataSent = true;
                 sendStatusFromServerTcs = new TaskCompletionSource<object>();
-                if (optionalWrite != null)
+                if (optionalWrite.HasValue)
                 {
                     streamingWritesCounter++;
                 }
@@ -227,5 +227,31 @@ namespace Grpc.Core.Internal
 
             finishedServersideTcs.SetResult(null);
         }
+
+        IReceivedCloseOnServerCallback ReceiveCloseOnServerCallback => this;
+
+        void IReceivedCloseOnServerCallback.OnReceivedCloseOnServer(bool success, bool cancelled)
+        {
+            HandleFinishedServerside(success, cancelled);
+        }
+
+        ISendStatusFromServerCompletionCallback SendStatusFromServerCompletionCallback => this;
+
+        void ISendStatusFromServerCompletionCallback.OnSendStatusFromServerCompletion(bool success)
+        {
+            HandleSendStatusFromServerFinished(success);
+        }
+
+        public struct ResponseWithFlags
+        {
+            public ResponseWithFlags(TResponse response, WriteFlags writeFlags)
+            {
+                this.Response = response;
+                this.WriteFlags = writeFlags;
+            }
+
+            public TResponse Response { get; }
+            public WriteFlags WriteFlags { get; }
+        }
     }
 }