message: Used keys to get stack size
  The scene items can have more items than the stack because it retains popped scenes to prevent their content being removed while the pop animation runs
diff: @@ -165,7 +165,7 @@ public class NavigationStackView extends ViewGroup {
  currentActivity.startActivity(intent);
  currentActivity.overridePendingTransition(enter, exit);
  }
  - oldCrumb = sceneItems.size() - 1;
  + oldCrumb = keys.size() - 1;
  }
  @Override
  