Tornado异步

http://www.tuicool.com/articles/36ZzA3

http://www.dongwm.com/archives/shi-yong-tornadorang-ni-de-qing-qiu-yi-bu-fei-zu-sai/

http://lbolla.info/blog/2013/01/22/blocking-tornado

http://www.tornadoweb.org/en/branch3.2/gen.html

http://www.cnblogs.com/yiwenshengmei/archive/2011/06/08/understanding_tornado.html