How to catch a flutter cloud firestore permission-denied error with a stream

Question

I'm noticing an issue where I can't catch a permission-denied error from cloud firestore with a stream in a flutter app.

I have this repository which is supposed to generate a stream of documents, and I have my security rules set to prevent all reading of documents.

I try catching all Exceptions, and then catching everything, and while breakpoints show an Exception is being thrown for 'permission-denied' from Cloud Firestore, the method never hits either of the catch blocks, and I get a message in VS Code saying I had an unhandled exception. Is there anything I'm missing here?

@override
  Stream<List<Habit>> watchMyActiveHabits() async* {
    try {
      final userDoc = await _firestore.userDocument();

      yield* userDoc
          .collection('habits')
          .withConverter(
            fromFirestore: (snapshot, _) => Habit.fromJson(snapshot.data()!),
            toFirestore: (habit, _) => habit.toJson(),
          )
          .where('active', isEqualTo: true)
          .snapshots()
          .map((snapshot) => snapshot.docs.map((doc) => doc.data()).toList());
    } on Exception catch (e) {
      _log.e('Exception: $e');
      rethrow;
    } catch (e) {
      _log.e('Unknown error: $e');
      rethrow;
    }
  }

I am using the Flutter bloc pattern and have this bloc that triggers that method and is supposed to return a state if an exception occurs, but it just hangs in the loadInProgress state:

  HabitWatcherBloc(this._habitRepository) : super(const _Initial()) {
    on<_Started>((event, emit) {
      emit(const HabitWatcherState.loadInProgress());
      try {
         _habitStreamSubscription =
            _habitRepository.watchMyActiveHabits().listen((habits) {
          emit(HabitWatcherState.loadSuccess(habits));
        });
      } on Exception catch (e) {
        emit(HabitWatcherState.loadFailure(e));
      }
    });
  }
}