notes/pl/java/libfws/fp/frp/rxjava/docs/whatsnew.txt

3.x
https://github.com/ReactiveX/RxJava/wiki/What's-different-in-3.0
    https://habr.com/ru/company/simbirsoft/blog/510400/
    https://prog.world/whats-new-in-rxjava-3/