Observer和Observables 是什么

https://android.jlelse.eu/be-reactive-develop-your-next-app-with-rxjava-4f00bfde0020?source=post_page---------------------------

What is Reactive Programming?
The Observer pattern is a software design pattern where in data sources or streams called Observables emit data and one or more Observers who are interested in getting the data subscribe to the observable.
翻译：
Observer发送数据，observable对感兴趣的数据订阅到observable