code: @Override
    public void channelRead(
        final ChannelHandlerContext ctx, final Object msg) throws Exception {
      try {
        this.listener.channelRead(ctx, msg);
      } finally {
        ReferenceCountUtil.release(msg);
      }
    }
docs: Handle the incoming message: pass it to the listener.
  
  @param ctx the context object for this handler.
  @param msg the message.
  @throws Exception