RxJava Combining Observable

combineLatest metodu
Şöyle yaparız.

Observable<Integer> source;
Observable<Integer> control;

Observable.combineLatest(source, control, (s, c) -> ...).filter(val -> ...)

withLatestFrom metodu
Şöyle yaparız.

source.withLatestFrom(control,
 BiFunction<Int, Int, Pair<Int, Int>>
   { sourceValue, controlValue -> Pair(sourceValue, controlValue) })
 .filter({ it.first <= it.second })