anchor.diff:    Future<int> build({
       String assetBase: _kDefaultAssetBase,
       String mainPath: _kDefaultMainPath,
  -    String manifestPath,
  +    String manifestPath: _kDefaultManifestPath,
       String outputPath: _kDefaultOutputPath,
       String snapshotPath: _kDefaultSnapshotPath,
       String privateKeyPath: _kDefaultPrivateKeyPath,
  
positive.code: 
  const String _kDefaultAssetBase = 'packages/material_design_icons/icons';
  const String _kDefaultMainPath = 'lib/main.dart';
  const String _kDefaultOutputPath = 'app.flx';
  const String _kDefaultSnapshotPath = 'snapshot_blob.bin';
  const String _kDefaultPrivateKeyPath = 'privatekey.der';
  
negative.code: }
  
  dynamic _loadManifest(String manifestPath) {
    if (manifestPath == null || !FileSystemEntity.isFileSync(manifestPath))
      return null;
    String manifestDescriptor = new File(manifestPath).readAsStringSync();
    return loadYaml(manifestDescriptor);
  