auth method

Implementation

@override
Future<bool> auth(String reason) async {
  final LocalAuthentication localAuth = LocalAuthentication();
  try {
    final bool didAuthenticate = await localAuth.authenticate(
        localizedReason: reason, authMessages: TBIBAuth.values);
    return didAuthenticate;
    // ···
  } on PlatformException {
    rethrow;
  }
}