Listen to auth events

1// Do not forget to import the following for StreamSubscription
2import 'dart:async';
3
4StreamSubscription<HubEvent> hubSubscription = Amplify.Hub.listen([HubChannel.Auth], (hubEvent) {
5  switch(hubEvent.eventName) {
6    case 'SIGNED_IN':
7      print('USER IS SIGNED IN');
8      break;
9    case 'SIGNED_OUT':
10      print('USER IS SIGNED OUT');
11      break;
12    case 'SESSION_EXPIRED':
13      print('SESSION HAS EXPIRED');
14      break;
15    case 'USER_DELETED':
16      print('USER HAS BEEN DELETED');
17      break;
18  }
19});