readByIds method
Fetch multiple items by their IDs.
Implementation
@override
Future<Map<String, T>> readByIds(List<String> ids, {required String userId}) async {
final byId = _storage[userId];
if (byId == null) return {};
return {
for (final id in ids)
if (byId.containsKey(id)) id: _fresh(byId[id]!),
};
}