anchor.diff:  /// A class that exposes the public API of a running Flutter Web App running.
   @JS()
   @anonymous
  +@staticInterop
   abstract class FlutterApp {
     /// Cleans a Flutter app
     external factory FlutterApp();
  
positive.code: /// and returns a promise of a FlutterAppCleaner.
  @JS()
  @anonymous
  abstract class FlutterAppRunner {
    /// Runs a flutter app
    external factory FlutterAppRunner({
  
negative.code: /// and run a Flutter Web app, from JavaScript.
  @JS()
  @anonymous
  @staticInterop
  abstract class FlutterEngineInitializer{
    external factory FlutterEngineInitializer({
      required InitializeEngineFn initializeEngine,
  