loadItems method
Implementation
Future<void> loadItems() async {
if (isClosed) return;
emit(ListLoading<T>());
try {
final items = await fetchItems();
if (isClosed) return;
emit(createLoadedState(items));
} catch (e) {
if (isClosed) return;
emit(ListError<T>(error: ErrorMapper.map(e)));
}
}