[cloud_firestore] Does cloud_firestore optimize duplicate snapshot listeners?

[kaiserschmarrn0]

This is not a feature request, just important information for app design.

If I open a duplicate snapshot listener will cloud_firestore check for an existing data stream and attach the listener to that stream?

A quick test suggests no, since neither stream objects or references are the same.

Code:

final ref1 = FirebaseFirestore.instance.collection('user').doc(user.uid);
final ref2 = FirebaseFirestore.instance.collection('user').doc(user.uid);
print(ref1.hashCode);
print(ref2.hashCode);
print('same: ${identical(ref1, ref2)}');

final st1 = ref1.snapshots();
final st2 = ref2.snapshots();
print(st1.hashCode);
print(st2.hashCode);
print('same: ${identical(st1, st2)}');

Output:

I/flutter (22234): 71130838
I/flutter (22234): 210352821
I/flutter (22234): same: false
I/flutter (22234): 526075342
I/flutter (22234): 955443828
I/flutter (22234): same: false

I couldn't find anywhere in the source that this optimization is made (it might be part of the android library or something, in my case), but its still possible that it happens and cloud_firestore just creates extra reference/stream objects for some design reason.