https://people.eecs.berkeley.edu/~sangjin/2012/12/21/epoll-vs-kqueue.html
http://www.kegel.com/c10k.html
http://nginx.org/en/docs/events.html
http://man7.org/linux/man-pages/man2/select.2.html
http://kukuruku.co/hub/cpp/lightweight-http-server-in-less-than-40-lines-on-libevent-and-c-11
http://lwn.net/Articles/520012/