class SingleOnErrorResume extends CompletionSingle<T> {

    @Override
    public void subscribe(Flow.Subscriber<? super T> subscriber) {
        Objects.requireNonNull(subscriber, "subscriber is null");
        source.subscribe(new OnErrorResumeSubscriber<>(subscriber, fallbackFunction));
    }

      SingleOnErrorResume(Single<T> source,
                        Function<? super Throwable, ? extends T> fallbackFunction);

}