anchor.diff:  // Copyright 2014 The Flutter Authors. All rights reserved.
   // Use of this source code is governed by a BSD-style license that can be
   // found in the LICENSE file.
  -
  -// @dart = 2.8
   
   import 'package:file/file.dart';
   import 'package:file/local.dart';
  
positive.code: 
  /// Host machine running the tests.
  class HostAgent {
    HostAgent({@required Platform platform, @required FileSystem fileSystem})
        : _platform = platform,
          _fileSystem = fileSystem;
  
  
negative.code:   final FileSystem _fileSystem;
  
    /// Creates a directory to dump file artifacts.
    Directory? get dumpDirectory {
      if (_dumpDirectory == null) {
        // Set in LUCI recipe.
        final String? directoryPath = _platform.environment['FLUTTER_LOGS_DIR'];
        if (directoryPath != null) {
          _dumpDirectory = _fileSystem.directory(directoryPath)..createSync(recursive: true);
          print('Found FLUTTER_LOGS_DIR dump directory ${_dumpDirectory?.path}');
        }
      }
      return _dumpDirectory;
    }
  
    static Directory? _dumpDirectory;
  
    @visibleForTesting
    void resetDumpDirectory() {
  