A function that converts a ValueListenable to a Stream

value_listenable_stream.dart

Stream<T> valueListenableToStreamAdapter<T>(ValueListenable<T> listenable) {
  StreamController<T> controller;

  void listener() {
    controller.add(listenable.value);
  }

  void start() {
    listenable.addListener(listener);
  }

  void end() {
    listenable.removeListener(listener);
  }

  controller = StreamController<T>(
    onListen: start,
    onPause: end,
    onResume: start,
    onCancel: end,
  );

  return controller.stream;
}

to prevent warnings for using the controller before it's assigned you should declare it with the late keyword:
late StreamController<T> controller;