The settings for this route.
See RouteSettings for details.
The settings can change during the route's lifetime. If the settings change, the route's overlays will be marked dirty (see changedInternalState).
If the route is created from a Page in the Navigator.pages list, then this will be a Page subclass, and it will be updated each time its corresponding Page in the Navigator.pages has changed. Once the Route is removed from the history, this value stops updating (and remains with its last value).
RouteSettings get settings => _settings;