@Override
      public void operationComplete(Future<Void> future) throws Exception {
        if (future.isSuccess()) {
          // setup response processing pipeline first, then send request.
          processWriteBlockResponse(channel, dnInfo, promise, timeoutMs);
          requestWriteBlock(channel, storageType, writeBlockProtoBuilder);
        } else {
          promise.tryFailure(future.cause());
        }
      }
Helper class for implementing {@link FanOutOneBlockAsyncDFSOutput}.
hbase-asyncfs/src/main/java/org/apache/hadoop/hbase/io/asyncfs/FanOutOneBlockAsyncDFSOutputHelper.java