anchor.diff:      String manifestPath,
       String outputPath: _kDefaultOutputPath,
       String snapshotPath: _kDefaultSnapshotPath,
  -    String privateKeyPath: _kDefaultPrivateKeyPath
  +    String privateKeyPath: _kDefaultPrivateKeyPath,
  +    bool precompiledSnapshot: false
     }) async {
       Map manifestDescriptor = _loadManifest(manifestPath);
   
  
positive.code:       manifestPath: argResults['manifest'],
        outputPath: argResults['output-file'],
        snapshotPath: argResults['snapshot'],
        privateKeyPath: argResults['private-key']
      );
    }
  
  
negative.code:   final String description = 'Create a Flutter app.';
  
    BuildCommand() {
      argParser.addFlag('precompiled', negatable: false);
      argParser.addOption('asset-base', defaultsTo: _kDefaultAssetBase);
      argParser.addOption('compiler');
      argParser.addOption('main', defaultsTo: _kDefaultMainPath);
      argParser.addOption('manifest');
  