Parallel networking calls in Dart 2

order_details_bloc.dart

 @override
  Stream<OrderDetailsState> mapEventToState(
    OrderDetailsEvent event,
  ) async* {
    if (event is ShowOrderDetails) {
      yield OrderDetailsState.loading();
      try {
        final account = await _authRepository.refreshToken();
        final results = await Future.wait(
          [
            _ordersRepository.fetchQuestionnaire(
              id: event.id,
              account: account,
            ),
            _ordersRepository.fetchMeta(
              id: event.id,
              account: account,
            )
          ],
        );
        yield OrderDetailsState.success(results[0], results[1]);
      } catch (error) {
        yield OrderDetailsState.failure(error.toString());
      }
    }
  }