anchor.diff:    final Set<String> excludedFiles = <String>{
       path.join(flutterLib, 'src', 'foundation', 'object.dart'), // Calls this from within an assert.
     };
  -  final List<File> files = _allFiles(flutterLib, 'dart', minimumMatches: 400)
  +  final List<File> files = await _allFiles(flutterLib, 'dart', minimumMatches: 400)
         .where((File file) => !excludedFiles.contains(file.path))
         .toList();
     final RegExp toStringRegExp = RegExp(r'^\s+String\s+to(.+?)?String(.+?)?\(\)\s+(\{|=>)');
  
positive.code: }
  
  Future<void> verifyNoTrailingSpaces(String workingDirectory, { int minimumMatches = 4000 }) async {
    final List<File> files = _allFiles(workingDirectory, null, minimumMatches: minimumMatches)
      .where((File file) => path.basename(file.path) != 'serviceaccount.enc')
      .where((File file) => path.basename(file.path) != 'Ahem.ttf')
      .where((File file) => path.extension(file.path) != '.snapshot')
  
negative.code:     printProgress('SKIPPING', relativeWorkingDir, commandDescription);
      return null;
    }
  
    if (!runSilently) {
      printProgress('RUNNING', relativeWorkingDir, commandDescription);
    }
  
    final Stopwatch time = Stopwatch()..start();
    final Process process = await Process.start(executable, arguments,
  