延迟和间隔运算符不能正常工作

如下所示,我正在创建 Observables 接线员。我希望代码能等5秒钟 System.out.println 从要打印的观察者。

doOnNext doOnNext公司 即使在5秒之后。

代码 :

public static void main(String[] args) {
    Observable<List<Person>> observables = Observable.create(e-> {
        for(List<Person> p : Main.getPersons()) {
            e.onNext(p);
        }
        e.onComplete();
    });
     observables
    //.subscribeOn(Schedulers.newThread())//newThread
    .flatMap(p->Main.toObservable(p.get(0).getName()))
    .doOnNext(p-> System.out.println(p.length()) )
    .map(p->p+"..STRING")
    //.delay(5, TimeUnit.SECONDS)
    //.interval(0, 5, TimeUnit.SECONDS)
    .observeOn(Schedulers.io())
    .subscribe(new Observer() {
        @Override
        public void onComplete() {
            // TODO Auto-generated method stub
            System.out.println("onCompleted");
        }

        @Override
        public void onError(Throwable arg0) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onNext(Object arg0) {
            // TODO Auto-generated method stub
            System.out.println("onNextFromObserver: " + arg0);
        }

        @Override
        public void onSubscribe(Disposable arg0) {
            // TODO Auto-generated method stub
        }
    });
}

private static <T> Observable<T> toObservable(T s) {
    return Observable.just(s);
}

private static List<List<Person>> getPersons() {
    return Arrays.asList(
            Arrays.asList(new Person("Sanna1", 59, "EGY"), new Person("Sanna2", 59, "EGY"), new Person("Sanna3", 59, "EGY")),
            Arrays.asList(new Person("Mohamed1", 59, "EGY"), new Person("Mohamed2", 59, "EGY")),
            Arrays.asList(new Person("Ahmed1", 44, "QTR"), new Person("Ahmed2", 44, "QTR"), new Person("Ahmed3", 44, "QTR")),
                    Arrays.asList(new Person("Fatma", 29, "KSA")),
                    Arrays.asList(new Person("Lobna", 24, "EGY"))
                    );
}