anchor.diff:    }
   
     Future _scan() async {
  +    final now = DateTime.now().toUtc();
       final query = _db.query<Package>()..order('created');
       if (_lastTs != null) {
         query.filter('created >', _lastTs);
  
positive.code:     await for (Package p in query.run()) {
        if (_stopped) return;
        nameTracker.add(p.name);
        _lastTs = p.created;
      }
    }
  
    void stop() {
  
negative.code: import 'models.dart';
  
  final _logger = Logger('pub.name_tracker');
  const _pollingInterval = Duration(minutes: 15);
  
  /// Sets the active [NameTracker].
  void registerNameTracker(NameTracker value) =>
  