RealmNotificationEnabledViewController.swift

final class DataDisplayViewController: UIViewController {
    
    private var realmNotificationToken: NotificationToken?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        startRealmNotification()
    }
    
    private func startRealmNotification() {
        do {
            let realm = try Realm()
            realmNotificationToken = realm.addNotificationBlock() { [weak self] _, _ in
                // TODO:- UPDATE UI
            }
        } catch {
            print("Error setting up Realm Notification: \(error.localizedDescription)")
        }
    }
  
    deinit {
        realmNotificationToken?.stop()
    }
}