Listen to auth events

1override func viewDidLoad() {
2    super.viewDidLoad()
3    // Do any additional setup after loading the view.
4
5    // Assumes `unsubscribeToken` is declared as an instance variable in your view
6    unsubscribeToken = Amplify.Hub.listen(to: .auth) { payload in
7        switch payload.eventName {
8        case HubPayload.EventName.Auth.signedIn:
9            print("User signed in")
10            // Update UI
11
12        case HubPayload.EventName.Auth.sessionExpired:
13            print("Session expired")
14            // Re-authenticate the user
15
16        case HubPayload.EventName.Auth.signedOut:
17            print("User signed out")
18            // Update UI
19
20        case HubPayload.EventName.Auth.userDeleted:
21            print("User deleted")
22            // Update UI
23
24        default:
25            break
26        }
27    }
28}