code: protected final ChannelFuture doConnect(InetSocketAddress target)
  	{
  		ChannelHandler fixHandler=fixHandlerBeforeConnect(channelInitFix(handler));//修正handler
  		return doBooterConnect(target, fixHandler);
  	}
docs: 对handler进行调整后调用启动器发起连接
  @param target
  @return