make SendStatusFromServer optionally send a message as well

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

@@ -165,7 +165,8 @@ namespace Grpc.Core.Internal.Tests
             SendCompletionHandler = callback;
         }
 
-        public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
+        public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata,
+            byte[] optionalPayload, WriteFlags writeFlags)
         {
             SendStatusFromServerHandler = callback;
         }

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

@@ -149,7 +149,8 @@ namespace Grpc.Core.Internal
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(trailers))
                 {
-                    call.StartSendStatusFromServer(HandleSendStatusFromServerFinished, status, metadataArray, !initialMetadataSent);
+                    call.StartSendStatusFromServer(HandleSendStatusFromServerFinished, status, metadataArray, !initialMetadataSent,
+                        null, new WriteFlags());
                 }
                 halfcloseRequested = true;
                 initialMetadataSent = true;

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

@@ -135,13 +135,16 @@ namespace Grpc.Core.Internal
             }
         }
 
-        public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
+        public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata,
+            byte[] optionalPayload, WriteFlags writeFlags)
         {
             using (completionQueue.NewScope())
             {
                 var ctx = BatchContextSafeHandle.Create();
+                var optionalPayloadLength = optionalPayload != null ? new UIntPtr((ulong)optionalPayload.Length) : UIntPtr.Zero;
                 completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
-                Native.grpcsharp_call_send_status_from_server(this, ctx, status.StatusCode, status.Detail, metadataArray, sendEmptyInitialMetadata).CheckOk();
+                Native.grpcsharp_call_send_status_from_server(this, ctx, status.StatusCode, status.Detail, metadataArray, sendEmptyInitialMetadata,
+                    optionalPayload, optionalPayloadLength, writeFlags).CheckOk();
             }
         }
 

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

@@ -78,7 +78,7 @@ namespace Grpc.Core.Internal
 
         void StartSendCloseFromClient(SendCompletionHandler callback);
 
-        void StartSendStatusFromServer(SendCompletionHandler callback, Grpc.Core.Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata);
+        void StartSendStatusFromServer(SendCompletionHandler callback, Grpc.Core.Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata, byte[] optionalPayload, Grpc.Core.WriteFlags writeFlags);
 
         void StartServerSide(ReceivedCloseOnServerHandler callback);
     }

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

@@ -421,20 +421,21 @@ namespace Grpc.Core.Internal
             public delegate GRPCCallError grpcsharp_call_cancel_delegate(CallSafeHandle call);
             public delegate GRPCCallError grpcsharp_call_cancel_with_status_delegate(CallSafeHandle call, StatusCode status, string description);
             public delegate GRPCCallError grpcsharp_call_start_unary_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
             public delegate GRPCCallError grpcsharp_call_start_client_streaming_delegate(CallSafeHandle call,
                 BatchContextSafeHandle ctx, MetadataArraySafeHandle metadataArray);
             public delegate GRPCCallError grpcsharp_call_start_server_streaming_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len,
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen,
                 MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
             public delegate GRPCCallError grpcsharp_call_start_duplex_streaming_delegate(CallSafeHandle call,
                 BatchContextSafeHandle ctx, MetadataArraySafeHandle metadataArray);
             public delegate GRPCCallError grpcsharp_call_send_message_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len, WriteFlags writeFlags, bool sendEmptyInitialMetadata);
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, WriteFlags writeFlags, bool sendEmptyInitialMetadata);
             public delegate GRPCCallError grpcsharp_call_send_close_from_client_delegate(CallSafeHandle call,
                 BatchContextSafeHandle ctx);
             public delegate GRPCCallError grpcsharp_call_send_status_from_server_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, StatusCode statusCode, string statusMessage, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata);
+                BatchContextSafeHandle ctx, StatusCode statusCode, string statusMessage, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata,
+                byte[] optionalSendBuffer, UIntPtr optionalSendBufferLen, WriteFlags writeFlags);
             public delegate GRPCCallError grpcsharp_call_recv_message_delegate(CallSafeHandle call,
                 BatchContextSafeHandle ctx);
             public delegate GRPCCallError grpcsharp_call_recv_initial_metadata_delegate(CallSafeHandle call,
@@ -593,7 +594,7 @@ namespace Grpc.Core.Internal
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_start_unary(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_start_client_streaming(CallSafeHandle call,
@@ -601,7 +602,7 @@ namespace Grpc.Core.Internal
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_start_server_streaming(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len,
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen,
                 MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
 
             [DllImport("grpc_csharp_ext.dll")]
@@ -610,7 +611,7 @@ namespace Grpc.Core.Internal
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_send_message(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len, WriteFlags writeFlags, bool sendEmptyInitialMetadata);
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, WriteFlags writeFlags, bool sendEmptyInitialMetadata);
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_send_close_from_client(CallSafeHandle call,
@@ -618,7 +619,8 @@ namespace Grpc.Core.Internal
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_send_status_from_server(CallSafeHandle call,
-                BatchContextSafeHandle ctx, StatusCode statusCode, string statusMessage, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata);
+                BatchContextSafeHandle ctx, StatusCode statusCode, string statusMessage, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata,
+                byte[] optionalSendBuffer, UIntPtr optionalSendBufferLen, WriteFlags writeFlags);
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_recv_message(CallSafeHandle call,

src/csharp/ext/grpc_csharp_ext.c

@@ -715,10 +715,11 @@ grpcsharp_call_send_close_from_client(grpc_call *call,
 GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_send_status_from_server(
     grpc_call *call, grpcsharp_batch_context *ctx, grpc_status_code status_code,
     const char *status_details, grpc_metadata_array *trailing_metadata,
-    int32_t send_empty_initial_metadata) {
+    int32_t send_empty_initial_metadata, const char* optional_send_buffer,
+    size_t optional_send_buffer_len, uint32_t write_flags) {
   /* TODO: don't use magic number */
-  grpc_op ops[2];
-  size_t nops = send_empty_initial_metadata ? 2 : 1;
+  grpc_op ops[3];
+  size_t nops = 1;
   ops[0].op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   ops[0].data.send_status_from_server.status = status_code;
   ops[0].data.send_status_from_server.status_details =
@@ -731,12 +732,23 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_send_status_from_server(
       ctx->send_status_from_server.trailing_metadata.metadata;
   ops[0].flags = 0;
   ops[0].reserved = NULL;
-  ops[1].op = GRPC_OP_SEND_INITIAL_METADATA;
-  ops[1].data.send_initial_metadata.count = 0;
-  ops[1].data.send_initial_metadata.metadata = NULL;
-  ops[1].flags = 0;
-  ops[1].reserved = NULL;
-
+  if (optional_send_buffer) {
+    ops[nops].op = GRPC_OP_SEND_MESSAGE;
+    ctx->send_message = string_to_byte_buffer(optional_send_buffer,
+                                              optional_send_buffer_len);
+    ops[nops].data.send_message = ctx->send_message;
+    ops[nops].flags = write_flags;
+    ops[nops].reserved = NULL;
+    nops ++;
+  }
+  if (send_empty_initial_metadata) {
+    ops[nops].op = GRPC_OP_SEND_INITIAL_METADATA;
+    ops[nops].data.send_initial_metadata.count = 0;
+    ops[nops].data.send_initial_metadata.metadata = NULL;
+    ops[nops].flags = 0;
+    ops[nops].reserved = NULL;
+    nops++;
+  }
   return grpc_call_start_batch(call, ops, nops, ctx, NULL);
 }