http://blog.csdn.net/hudon/article/details/1506042
http://www.cnblogs.com/biakia/p/4779655.html
http://oldratlee.com/post/2013-02-01/synchronous-rpc-vs-asynchronous-message/
http://www.cnblogs.com/tangyanbo/p/4499485.html
http://www.cnblogs.com/LBSer/p/4622749.html
备注：
1. https://www.zhihu.com/question/22764869