anchor.diff:    Future<Null> cancel() => _stopScrapingLogs();
   
     Future<Null> _stopScrapingLogs() async {
  -    _timer?.cancel();
  -    _timer = null;
       await _deviceLogSubscription?.cancel();
       _deviceLogSubscription = null;
     }
  
positive.code:     if (portForwarder != null) {
        final int devicePort = deviceUri.port;
        int hostPort = this.hostPort ?? await portScanner.findPreferredPort(defaultHostPort);
        hostPort = await portForwarder
            .forward(devicePort, hostPort: hostPort)
            .timeout(const Duration(seconds: 60), onTimeout: () {
          throwToolExit('Timeout while atempting to foward device port $devicePort for $serviceName');
        });
        printTrace('Forwarded host port $hostPort to device port $devicePort for $serviceName');
        hostUri = deviceUri.replace(port: hostPort);
      }
  
negative.code:   final Completer<Uri> _completer = new Completer<Uri>();
  
    StreamSubscription<String> _deviceLogSubscription;
  
    /// The discovered service URI.
    Future<Uri> get uri => _completer.future;
  