netty: Associate netty stream eagerly to avoid client hang

netty/src/main/java/io/grpc/netty/NettyClientHandler.java

@@ -768,6 +768,19 @@ public void operationComplete(ChannelFuture future) throws Exception {
             }
           }
         });
+    // When the HEADERS are not buffered because of MAX_CONCURRENT_STREAMS in
+    // StreamBufferingEncoder, the stream is created immediately even if the bytes of the HEADERS
+    // are delayed because the OS may have too much buffered and isn't accepting the write. The
+    // write promise is also delayed until flush(). However, we need to associate the netty stream
+    // with the transport state so that goingAway() and forcefulClose() and able to notify the
+    // stream of failures.
+    //
+    // This leaves a hole when MAX_CONCURRENT_STREAMS is reached, as http2Stream will be null, but
+    // it is better than nothing.
+    Http2Stream http2Stream = connection().stream(streamId);
+    if (http2Stream != null) {
+      http2Stream.setProperty(streamKey, stream);
+    }
   }
 
   /**

netty/src/test/java/io/grpc/netty/NettyClientHandlerTest.java

@@ -453,6 +453,26 @@ public void receivedAbruptGoAwayShouldFailRacingQueuedStreamid() throws Exceptio
     assertTrue(future.isDone());
   }
 
+  @Test
+  public void receivedAbruptGoAwayShouldFailRacingQueuedIoStreamid() throws Exception {
+    // Purposefully avoid flush(), since we want the write to not actually complete.
+    // EmbeddedChannel doesn't support flow control, so this is the next closest approximation.
+    ChannelFuture future = channel().write(
+        newCreateStreamCommand(grpcHeaders, streamTransportState));
+    // Read a GOAWAY that indicates our stream can't be sent
+    channelRead(goAwayFrame(0, 0 /* NO_ERROR */, Unpooled.copiedBuffer("this is a test", UTF_8)));
+
+    ArgumentCaptor<Status> captor = ArgumentCaptor.forClass(Status.class);
+    verify(streamListener).closed(captor.capture(), same(REFUSED),
+        ArgumentMatchers.<Metadata>notNull());
+    assertEquals(Status.UNAVAILABLE.getCode(), captor.getValue().getCode());
+    assertEquals(
+        "Abrupt GOAWAY closed sent stream. HTTP/2 error code: NO_ERROR, "
+          + "debug data: this is a test",
+        captor.getValue().getDescription());
+    assertTrue(future.isDone());
+  }
+
   @Test
   public void receivedGoAway_shouldFailBufferedStreamsExceedingMaxConcurrentStreams()
       throws Exception {