转自：
https://www.cnblogs.com/dongweiq/p/5253160.html
https://www.aliyun.com/jiaocheng/26839.html
https://blog.csdn.net/youniworld/article/details/47300019
微信智能心跳方案
原文：https://www.cnblogs.com/yorkyang/p/9936614.html
