message: Typed to nav bar view for clarity
  Not tested with generic app bar layout so no point coding for it
diff: @@ -65,8 +65,8 @@ public class TabNavigationView extends BottomNavigationView implements TabView {
  if (tabBarItem instanceof ViewGroup) {
  ViewGroup viewGroup = (ViewGroup) tabBarItem;
  for(int i = 0; i < viewGroup.getChildCount(); i++) {
  - if (viewGroup.getChildAt(i) instanceof AppBarLayout)
  - ((AppBarLayout) viewGroup.getChildAt(i)).setExpanded(true);
  + if (viewGroup.getChildAt(i) instanceof NavigationBarView)
  + ((NavigationBarView) viewGroup.getChildAt(i)).setExpanded(true);
  if (viewGroup.getChildAt(i) instanceof ScrollView)
  ((ScrollView) viewGroup.getChildAt(i)).smoothScrollTo(0,0);
  }
  