How Can I use a Riverpod Provider from within a SliverList?

I've got a small Flutter widget that should show a list of items via a Riverpod provider. I'm having a hard time figuring out the proper way to handle the setup. My current code looks like this:

Widget build(BuildContext context, WidgetRef ref) {
    final listValue = ref.watch(listProvider);
    return Scaffold(
      body: CustomScrollView(
        slivers: [
          SliverAppBar...
          SliverList(
            delegate: SliverChildBuilderDelegate(
              (context, index) {
                return listValue.when(
                  data: (things) => ListTile(
                    title: things[index].name,
                    subtitle: things[index].date,
                  ),
                  error: (e, st) => SliverToBoxAdapter(
                      child: Center(child: Text('Error! $e'))),
                  loading: () => SliverToBoxAdapter(
                      child: const Center(
                          child: CircularProgressIndicator.adaptive())),
                );
              },
              childCount: // where do I get this? no access to listValue,
          ),
          SliverFillRemaining(),
        ])...

This works, but I get an error below the final list item since there's no childCount...

Extract listvalue.when to the top of the SliverList to get length value inside the Delegate and handle the errors gracefully here is the full code

Widget build(BuildContext context, WidgetRef ref) {
  final listValue = ref.watch(listProvider);

  return Scaffold(
    body: CustomScrollView(
      slivers: [
        SliverAppBar...
        listValue.when(
          data: (things) {
           if(things.isEmpty){
            return SliverToBoxAdapter(
                    child: Center(child: Text("No items available.")),
                  );
            }
           return SliverList(
                    delegate: SliverChildBuilderDelegate(
                      (context, index) => ListTile(
                        title: Text(things[index].name),
                        subtitle: Text(things[index].date),
                      ),
                      childCount: things.length,
                    ),
                  );
          },
          error: (e, st) => SliverToBoxAdapter(
            child: Center(child: Text('Error: $e')),
          ),
          loading: () => const SliverToBoxAdapter(
            child: Center(child: CircularProgressIndicator.adaptive()),
          ),
        ),

        const SliverFillRemaining(),
      ],
    ),
  );
}