Rx2java使用kotlin来写一下。常见操作符，
主要包括：
- just
- buffer
- debounce
- delay
- timer
- interval
- disposable
- distinct
- filter
- last
- map
- merge
- publishSubject
- reduce
- replay
- replaySubject
- scan
- doOnNext
- singleobservable
- skip
- take
- takeWhile
- throttleFirst
- throttleLast
- zip
废话不多说，直接上地址 https://github.com/AKJoson/Rx2java_kotlin_simple_case
