code: private ChannelHandler channelInitFix(final ChannelHandler handler)
  	{
  		ChannelHandler fixedHandler=new ShareableChannelInboundHandler() {
  			@Override
  			public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
  				Channel ch=ctx.channel();
  				setChannel(ch);
  				ctx.pipeline().addLast(handler);
  				ctx.pipeline().remove(this);//移除当前handler
  				ctx.fireChannelRegistered();//从当前handler往后抛出事件
  			}
  		};
  		return fixedHandler;
  	}
docs: 包装一个初始化父类channel的handler
  @param handler 业务handler
  @return