Are Firestore streams closed automatically upon garbage collection?

[Parakoos]

I cannot seem to work out if collection queries are automatically closed when a object is garbage collected. Say I have this class:

import 'package:cloud_firestore/cloud_firestore.dart';

class ExampleClass {
  final Stream<QuerySnapshot> collectionStream;
  ExampleClass(String collectionName)
      : this.collectionStream =
            FirebaseFirestore.instance.collection(collectionName).snapshots();
}

If I instantiate the class, use it, and then lose all references to the instance, expecting it to be garbage collected, what will happen? Will the stream be closed? If there are updates to the collection, will the reads happen (and thus be billed for?) Or perhaps the existence of an open stream will prevent the instance from being garbage collected?