1. override
void didPop(Route route, Route previousRoute)

The Navigator popped the given route.

Source 

@override
void didPop(Route<dynamic> route, Route<dynamic> previousRoute) {
  assert(navigator != null);
  assert(route != null);
  if (route is PageRoute<dynamic>) {
    assert(route.animation != null);
    if (route.animation.status != AnimationStatus.dismissed && previousRoute is PageRoute<dynamic>) {
      _from = route;
      _to = previousRoute;
      _animation = route.animation;
      _checkForHeroQuest();
    }
  }
}