Unix网络编程中的 5 种IO模型：https://www.jianshu.com/p/486b0965c296
- Blocking IO - 阻塞IO
- NoneBlocking IO - 非阻塞IO
- IO multiplexing - IO多路复用
- asynchronous IO - 异步IO
- signal driven IO - 信号驱动IO
零拷贝
https://baijiahao.baidu.com/s?id=1664128784220450138&wfr=spider&for=pc
epoll