Bloc returns an empty array, but renders a lot of widgets

Question

I'm trying to use BLoC as a state management in my application, and I encountered two problems I can't seem to fix. First, I always get a null value instead of the data. Second, although I get null value, the component still renders a lot of widgets.

This is my component:

StreamBuilder<List<CustomItem>>(
            stream: _itemsBloc.itemsStream,
            builder: ((context, snapshot) {
              final items = snapshot.data;
              return Expanded(
                child: ListView.builder(
                    scrollDirection: Axis.horizontal,
                    shrinkWrap: true,
                    itemCount: items?.length,
                    itemBuilder: (BuildContext context, int index) {
                      var i = items?[index];
                      return CustomItem(
                        name: e != null ? e.name : "",
                        color: e != null ? e.color : "",
                      );
                    }),
              );
            }),
          ),

This is my BLoC class:

enum ItemsEvent {
  fetch,
}

class ItemsBloc {
  final _eventController = StreamController<ItemsEvent>();
  Stream<ItemsEvent> get eventStream => _eventController.stream;
  Sink<ItemsEvent> get eventSink => _eventController.sink;

  final _itemsController = StreamController<List<CustomItem>>();
  Stream<List<CustomItem>> get itemsStream =>
      _itemsController.stream;
  Sink<List<CustomItem>> get itemsSink => _itemsController.sink;

  List<CustomItem> items = [];
  ItemsBloc() {
    eventStream.listen((ItemsEvent event) async {
      switch (event) {
        case ItemsEvent.fetch:
          items = await DataService.fetchItems();
          break;
        default:
      }
    });
  }
}

This is how I try to fetch the data from the component:

  @override
  void initState() {
    super.initState();
    _itemsBloc.eventSink.add(ItemsEvent.fetch);
  }

What is wrong here, and why the widgets still render although no data is provided?