rac冷信号与热信号区分

http://www.cnblogs.com/Jenaral/p/5656317.html

参考链接：

1.http://tech.meituan.com/talk-about-reactivecocoas-cold-signal-and-hot-signal-part-1.html

2.http://tech.meituan.com/talk-about-reactivecocoas-cold-signal-and-hot-signal-part-2.html

3.http://tech.meituan.com/talk-about-reactivecocoas-cold-signal-and-hot-signal-part-3.html

4.http://www.jianshu.com/p/d81636f79f80