Suggestion

[sasa0]

The sample app is cool. I am wondering why there are some unnecessary stuff, for ex:
if (subscription == null || (subscription != null && subscription.isUnsubscribed())){...}
Logically, you don't need this part: subscription != null &&

Thanks.

[klaszlo8207]

.map((item) -> randomItems ? (new Random().nextInt(20 - 0) + 0) : item )