addDataChangeListner method
Implementation
@override
void addDataChangeListner(Type model, String docId, Function onDataChanged) {
String collectionname = model.toString();
_usersStream = _db.collection(collectionname).doc(docId).snapshots();
_usersStream.listen(
(DocumentSnapshot<Object?> event) {
onDataChanged(event.data());
},
);
}