@Override
  protected ReactActivityDelegate createReactActivityDelegate() {
    return new MainActivityDelegate(this, getMainComponentName());
  }
Returns the instance of the {@link ReactActivityDelegate}. There the RootView is created and
you can specify the renderer you wish to use - the new renderer (Fabric) or the old renderer
(Paper).
template/android/app/src/main/java/com/helloworld/MainActivity.java