Observable<Task> taskObservable = Observable
        .fromIterable(DataSource.createTasksList())
        .take(3)
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread());

taskObservable.subscribe(new Observer<Task>() {
    @Override
    public void onSubscribe(Disposable d) {

    }
    @Override
    public void onNext(Task task) {
        Log.d(TAG, "onNext: " + task.getDescription());
    }
    @Override
    public void onError(Throwable e) {

    }
    @Override
    public void onComplete() {

    }
});