flutter_architecture_samples/firestore_redux/ how can I store the StreamSubscriptions?

Hi Brian, I'm looking for a solution for storing streamsubscriptions in my middleware. How I can store the streamsubscription and cancel them if i need too?

Especially in flutter_architecture_samples/firestore_redux/lib/middleware/store_todos_middleware.dart line 66 / 67 there is a listen() which returns a subscription but it is not stored? How do you cancel the subscription?

In the E-Mail from Nilay couple days ago, there was a suggestion for using streamsubscriptions and canceling them.

http://dart-lang.github.io/linter/lints/cancel_subscriptions.html

class B {
  StreamSubscription _subscriptionB; 
  void init(Stream stream) {
    _subscriptionB = stream.listen((_) {});
  }
  void dispose(filename) {
    _subscriptionB.cancel();
  }
}

And I need in my code the fully control of the subscriptions. I would very appreciate your answer.

Cheers, :)