How to create a Stream inside valueNotifier?

Question

I have a class that inherits from ValueNotifier. I need to create a Stream in it, which every 5 seconds generates 3 types of events (adding, deleting and changing) and sends them through ValueNotifier. It can be just a list with strings for these events. How can i do this?

class EventNotifier extends ValueNotifier {
EventNotifier (value) : super(value);
 final StreamSubscription? _streamSub = Stream.periodic(const Duration(seconds: 5)).listen((event) {

 });
}