combine
Returns an observable that combines the emissions of this observable the given other. The downstream emission is the result of applying the combiner function to the latest emissions of both observables - and are only possible once both this and the other have emitted at least one value.
open fun <T2, T3, R> combine(other1: Observable<T2>, other2: Observable<T3>, combiner: (T, T2, T3) -> R): Observable<R>
Returns an observable that combines the emissions of this observable the given others. The downstream emission is the result of applying the combiner function to the latest emissions of both observables - and are only possible once all others have emitted at least one value.