docs: @Override
      public void init(TCPWriteRequestContext x, H2MuxTCPWriteCallback c) {
          writeReqContext = x;
          muxCallback = c;
  
          // callback will need to know how to get back to this write queue.
          // This means one and only one H2WriteTree per H2InboundLink which has just one true TCP Channel facing write callback
          muxCallback.setH2WorkQ(this);
  
          tree = new Tree();
  
      }