class ObservableExt {

    public static <T> Observable<T> fromWithDelay(List<Observable<T>> chunks, long delay, TimeUnit timeUnit, Scheduler scheduler) {
        if (chunks.isEmpty()) {
            return Observable.empty();
        }
        final Iterator<Observable<T>> chunkIterator = chunks.iterator();
        Observable<T> result = chunkIterator.next();
        while (chunkIterator.hasNext()) {
            result = result.concatWith(chunkIterator.next().delay(delay, timeUnit, scheduler));
        }
        return result;
    }

}