reorder UnsafeSerialize

src/csharp/Grpc.Core.Tests/Internal/SliceBufferSafeHandleTest.cs

@@ -152,7 +152,6 @@ namespace Grpc.Core.Internal.Tests
 
         // TODO: other TODOs
         // -- provide a null instance of SliceBufferSafeHandle
-        //-- order of UnsafeSerialize in AsyncCall methods...
 
         private byte[] GetTestBuffer(int length)
         {

src/csharp/Grpc.Core/Internal/AsyncCall.cs

@@ -160,16 +160,15 @@ namespace Grpc.Core.Internal
                     halfcloseRequested = true;
                     readingDone = true;
 
-                    //var payload = UnsafeSerialize(msg);
-
-                    unaryResponseTcs = new TaskCompletionSource<TResponse>();
                     using (var serializationScope = DefaultSerializationContext.GetInitializedThreadLocalScope())
-                    using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
                     {
-                        var payload = UnsafeSerialize(msg, serializationScope.Context); // do before metadata array?
-
-                        call.StartUnary(UnaryResponseClientCallback, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
-                        callStartedOk = true;
+                        var payload = UnsafeSerialize(msg, serializationScope.Context);
+                        unaryResponseTcs = new TaskCompletionSource<TResponse>();
+                        using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                        {
+                            call.StartUnary(UnaryResponseClientCallback, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
+                            callStartedOk = true;
+                        }
                     }
 
                     return unaryResponseTcs.Task;
@@ -238,17 +237,15 @@ namespace Grpc.Core.Internal
 
                     halfcloseRequested = true;
 
-                    //var payload = UnsafeSerialize(msg);
-
-                    streamingResponseCallFinishedTcs = new TaskCompletionSource<object>();
-                    
                     using (var serializationScope = DefaultSerializationContext.GetInitializedThreadLocalScope())
-                    using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
                     {
-                        var payload = UnsafeSerialize(msg, serializationScope.Context); // do before metadata array?
-                        
-                        call.StartServerStreaming(ReceivedStatusOnClientCallback, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
-                        callStartedOk = true;
+                        var payload = UnsafeSerialize(msg, serializationScope.Context);
+                        streamingResponseCallFinishedTcs = new TaskCompletionSource<object>();
+                        using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                        {
+                            call.StartServerStreaming(ReceivedStatusOnClientCallback, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
+                            callStartedOk = true;
+                        }
                     }
                     call.StartReceiveInitialMetadata(ReceivedResponseHeadersCallback);
                 }

src/csharp/Grpc.Core/Internal/AsyncCallBase.cs

@@ -117,7 +117,7 @@ namespace Grpc.Core.Internal
         {
             using (var serializationScope = DefaultSerializationContext.GetInitializedThreadLocalScope())
             {
-                var payload = UnsafeSerialize(msg, serializationScope.Context); // do before metadata array?
+                var payload = UnsafeSerialize(msg, serializationScope.Context);
                 lock (myLock)
                 {
                     GrpcPreconditions.CheckState(started);