anchor.diff:  
       String snapshotPath = results['snapshot'];
       await _compileSnapshot(
  +      compilerPath: results['compiler'],
         mainPath: results['main'],
         packageRoot: results['package-root'],
         snapshotPath: snapshotPath);
  
positive.code:     ArgParser parser = new ArgParser();
      parser.addFlag('help', abbr: 'h', negatable: false);
      parser.addOption('asset-base', defaultsTo: 'packages/material_design_icons/icons');
      parser.addOption('main', defaultsTo: 'lib/main.dart');
      parser.addOption('manifest', defaultsTo: 'flutter.yaml');
      parser.addOption('output-file', abbr: 'o', defaultsTo: 'app.flx');
      parser.addOption('package-root', defaultsTo: 'packages');
      parser.addOption('snapshot', defaultsTo: 'snapshot_blob.bin');
  
negative.code: }
  
  Future _compileSnapshot({
    String compilerPath,
    String mainPath,
    String packageRoot,
    String snapshotPath
  }) async {
    File compiler = compilerPath == null ?
        await artifactStore.getPath(Artifact.FlutterCompiler) :
        new File(compilerPath);
    ProcessResult result = await Process.run(compiler.path, [
      mainPath,
      '--package-root=$packageRoot',
      '--snapshot=$snapshotPath'
    ]);
    if (result.exitCode != 0) {
      print(result.stdout);
      print(result.stderr);
      exit(result.exitCode);
    }
  }
  
  Future<ArchiveFile> _createSnapshotFile(String snapshotPath) async {
  