Netty相关ChildHandler

• IdleStateHandler
  心跳Handler
  https://blog.csdn.net/weixin_43935927/article/details/112001309

• LengthFieldPrepender
  将当前发送消息的二进制字节长度，添加到缓冲区头部
  https://blog.csdn.net/cgj296645438/article/details/90667419

• LengthFieldBasedFrameDecoder
  自定义长度解码器
  https://www.jianshu.com/p/64dc7ee8c713