anchor.diff:  
   library analyzer_cli.src.bootloader;
   
  -import 'dart:io';
   import 'dart:isolate';
   
   import 'package:analyzer/file_system/physical_file_system.dart';
  
positive.code:   /// `.analyzer_options` which is then run in a spawned isolate.
    void load() {
      List<PluginInfo> plugins = _validate(config.plugins);
  
      String mainSource = new Assembler(plugins).createMain();
  
      Uri uri =
          Uri.parse('data:application/dart;charset=utf-8,${Uri.encodeComponent(
              mainSource)}');
  
      ReceivePort errorListener = new ReceivePort();
      errorListener.listen((data) {
        //TODO(pquitslund): handle errors.
        print('>>> ERROR: $data');
      });
  
      ReceivePort exitListener = new ReceivePort();
      exitListener.listen((data) {
        // Propagate exit code.
        exit(exitCode);
      });
  
      // TODO(pquitslund): update once .packages are supported.
      String packageRoot =
          packageRootPath != null ? packageRootPath : './packages';
      Uri packageUri = new Uri.file(packageRoot);
  
      // TODO(pquitslund): add .packages support once the VM implements it.
      Isolate.spawnUri(uri, args, null /* msg */,
          packageRoot: packageUri,
          onError: errorListener.sendPort,
          onExit: exitListener.sendPort);
  
      // TODO(pquitslund): consider starting paused
      // http://stackoverflow.com/questions/29247374/what-is-the-best-way-to-track-the-state-of-an-isolate-in-dart
    }
  }
  
negative.code:     // All good.
      return null;
    }
    return 'Plugin ${plugin.name} skipped, config missing: ${missing.join(", ")}';
  }
  
  