dispose method
Important to call this function when terminating the you app.
Implementation
// However, doesn't not seem to be called?
Future<void> dispose() async {
await signOut();
_modAuth = null;
_mobGoogleSignIn = null;
_fireBaseListeners = null;
_googleListeners = null;
await _googleListener?.cancel();
await _firebaseListener?.cancel();
_googleListener = null;
_firebaseListener = null;
_facebookAuth = null;
_twitterLogin = null;
}