intervalObservable.subscribe(new Observer<Long>() {
    @Override
    public void onSubscribe(Disposable d) {
    }
    @Override
    public void onNext(Long aLong) {
        Log.d(TAG, "onNext: interval: " + aLong);
    }
    @Override
    public void onError(Throwable e) {

    }
    @Override
    public void onComplete() {

    }
});