[Flutter] Firebase Realtime Database .info/connected listener always says "false." (Flutter)

In a Flutter/Firebase app, I am trying to have a way of tracking whether users are "online" or not (for purposes of having a directory filterable by "is Online", for exmaple).

At the point in the app where the uid becomes known, I added this:

void _setUpPresenceListener(String uid) async {

// *** Un-used Realtime Database reference to keep the connection alive
DatabaseReference userStatusRef = FirebaseDatabase.instance.ref('status/$uid');

// Reference to the .info/connected node in Realtime Database
DatabaseReference connectedRef = FirebaseDatabase.instance.ref(".info/connected");

// Firestore reference to the users_presence collection
DocumentReference presenceRef = FirebaseFirestore.instance.collection('users_presence').doc(uid);

// Listen for connection state changes
connectedRef.onValue.listen((event) async {
final bool isConnected = event.snapshot.value as bool? ?? false;

// ***
print("&&& - val: ${event.snapshot.value.toString()}");

// If connected, set isOnline to true in Firestore
if (isConnected) {

await presenceRef.set({
'isOnline': true,
'lastChanged': FieldValue.serverTimestamp(),
});
} else {
// When disconnected, set isOnline to false
await presenceRef.set({
'isOnline': false,
'lastChanged': FieldValue.serverTimestamp(),
});
}
});
}


This resulted in the firestore data field always being set to false, so I investigated/troubleshooted(?) by adding the parts marked *** which further verified the issue -- printed value is explicit 'false'

Important points:

• Security Rules are not an issue since the field is being written to successfully.
• I am testing with an android emulator.
• I am not using realtime database for any other purpose in the app.

Is there some other pre-requisite to this listener refecting an accurate connection state?

I was considering whether the reason may be that I am not using realtime database for anything else... and so maybe .info/... is never initialized to anything meaningful because of this?

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