I am working in a flutter where I am expecting the UI to be updated with data when backend insert any in mongoDB collection. For futter I am using realm.

Currently I am trying to listen changes in mongoDB but it is not triggering when data getting inserted in to the mongoDB

Pasting my code here.

class UserPlantRepo extends UserPlantRepoInterface {
  final RealmServiceInterface _realmService;

  final localDataStream = StreamController<RealmResultsChanges<UserPlant>?>.broadcast();


  UserPlantRepo({
    required RealmServiceInterface realmService,
  }) : _realmService = realmService
  {
    localDataStream.stream.listen((event) {
     log("UserPlantRepo localDataStream event emitted $event");
   },onError: (error){
     log("UserPlantRepo localDataStream error emitted $error");
   },);
  }



  @override
  Future<UserPlantDataModelWrapper> getUserPlantsFromDB(
      {required String emailAddress}) async {
    try {
      await _realmService.updateSubscriptions<UserPlant>(
        r'userId==$0',
        [emailAddress],
      );
      final RealmResults<UserPlant>? response = await _realmService.fetchData(
        r'userId==$0',
        [
          emailAddress,
        ],
      );

      if(response != null){
        log("UserPlantRepo getUserPlantsFromDB response is not null");
       localDataStream.addStream(response.changes);
      }
     ;
      if (response != null) {
        if (response.isNotEmpty) {
          return UserPlantDataModelWrapper(
              isSuccess: true,
              userPlantDataModel: response.first.getUserPlants());
        } else {
          return UserPlantDataModelWrapper(
              isSuccess: true, userPlantDataModel: null);
        }
      } else {
        return UserPlantDataModelWrapper(
            isSuccess: true, userPlantDataModel: null);
      }
    } catch (e) {
      return UserPlantDataModelWrapper(
          isSuccess: true, userPlantDataModel: null);
    }
  }

  Stream<RealmResultsChanges<UserPlant>?> get getUpdateStatusStream => localDataStream.stream;
}

Please help on this.
Thanks in advance!!