fun <T, R> Observable<T>.fold(accumulator: R, folderFun: (R, T) -> Unit): R
fold takes an rx.Observable stream and applies fold function on it, and collects all elements using the accumulator.
accumulator
- The accumulator for accumulating elements.
folderFun
- The transformation function to be called on the observable list when a new element is emitted on
the stream, which should modify the list as needed.