replay

ConnectableObservable<Long> cold = Observable.interval(200, TimeUnit.MILLISECONDS).replay();
Subscription s = cold.connect();

System.out.println("Subscribe first");
Subscription s1 = cold.subscribe(i -> System.out.println("First: " + i));
Thread.sleep(700);
System.out.println("Subscribe second");
Subscription s2 = cold.subscribe(i -> System.out.println("Second: " + i));
Thread.sleep(500);