anchor.diff:          final Process flutterProcess = await inDirectory(appDir, () async {
             if (deviceOperatingSystem == DeviceOperatingSystem.ios)
               await prepareProvisioningCertificates(appDir.path);
  +          final List<String> options = <String>[
  +            '-v',
  +            // --release doesn't work on iOS due to code signing issues
  +            '--profile',
  +            '-d',
  +            device.deviceId,
  +          ];
  +          if (previewDart2)
  +            options.add('--preview-dart-2');
  +          options.add(benchmarkPath);
             return await _startFlutter(
  -            options: <String>[
  -              '-v',
  -              // --release doesn't work on iOS due to code signing issues
  -              '--profile',
  -              '-d',
  -              device.deviceId,
  -              benchmarkPath,
  -            ],
  +            options: options,
               canFail: false,
             );
           });
  
positive.code:     allResults.addAll(await _runMicrobench('lib/stocks/build_bench.dart'));
      allResults.addAll(await _runMicrobench('lib/gestures/velocity_tracker_bench.dart'));
      allResults.addAll(await _runMicrobench('lib/stocks/animation_bench.dart'));
  
      return new TaskResult.success(allResults, benchmarkScoreKeys: allResults.keys.toList());
    };
  
negative.code:     final Device device = await devices.workingDevice;
      await device.unlock();
  
      Future<Map<String, double>> _runMicrobench(String benchmarkPath, {bool previewDart2: false}) async {
        Future<Map<String, double>> _run() async {
          print('Running $benchmarkPath');
          final Directory appDir = dir(
  