anchor.diff:    final _packagesWithVersion = <String>{};
     final _publishers = <String>{};
     final _publishersAbandoned = <String>{};
  +  // package name -> versions
  +  final _badVersionInPubspec = <String, Set<String>>{};
     int _packageChecked = 0;
     int _versionChecked = 0;
     late http.Client _httpClient;
  
positive.code: 
    Future<bool> _packageMissing(String packageName) async =>
        !(await _packageExists(packageName));
  }
  
  Stream<String> _checkPubspec(String type, String key, Pubspec pubspec) async* {
    if (pubspec.hasBadVersionFormat) {
      yield '$type "$key" has bad version format in `pubspec`.';
    }
  }
  
negative.code:     yield* _checkLikes();
      yield* _checkModeratedPackages();
      yield* _checkAuditLogs();
      yield* _reportPubspecVersionIssues();
      _httpClient.close();
    }
  
  