UIViewControllers are deallocated on the main thread. (Why is UIViewController deallocated on the main thread?)
My UINavigationController has a UIViewController which is very memory-heavy (SceneKit Scene with thousands of nodes).
When User pushes back button, this UIViewController gets dismissed.
However, UI gets blocked for around 4 seconds until deallocation finishes.
How can I avoid the UI getting blocked while deallocation completes?
Or, how can I be notified when deallocation finished, so I can show a spinner while the UI is blocked?