relatica/lib/services/setting_service.dart

import 'package:flutter/foundation.dart';

class SettingsService extends ChangeNotifier {
  var _lowBandwidthMode = true;

  bool get lowBandwidthMode => _lowBandwidthMode;

  set lowBandwidthMode(bool value) {
    _lowBandwidthMode = value;
    notifyListeners();
  }
}