1.evpp

https://github.com/Qihoo360/evpp/tree/master/examples/recipes/self_control_timer

https://blog.csdn.net/zieckey/article/details/70245013

2.enable_shared_from_this

shared_ptr接收裸指针，更改引用计数。

shared_ptr接收shared_ptr，更改引用计数。

在类的内部获取shared_ptr需要shared_from_this。

https://www.zhihu.com/question/30957800

https://baike.baidu.com/item/shared_ptr/2708164?fr=aladdin

https://blog.csdn.net/caoshangpa/article/details/79392878

3.libevent timer

time-test.c

https://blog.csdn.net/u010090316/article/details/70833334