同步异步阻塞非阻塞概念

聊聊同步、异步、阻塞与非阻塞

https://www.jianshu.com/p/aed6067eeac9

聊聊Linux 五种IO模型

https://www.jianshu.com/p/486b0965c296

聊聊IO多路复用之select、poll、epoll详解

https://www.jianshu.com/p/dfd940e7fca2