make loadOlder properly guard

lib/controllers/room_chat.dart

@@ -75,12 +75,13 @@ class RoomChatController extends AsyncNotifier<IList<Event>?> {
       );
 
   Future<bool> loadOlder() async {
+    state = AsyncLoading();
     final timelineKeys = ref
         .read(RoomsController.provider.select((value) => value[roomId]))
         ?.timeline
         .keys;
     final response = await ref
-        .watch(ClientController.provider.notifier)
+        .read(ClientController.provider.notifier)
         .paginate(
           .new(
             roomId: roomId,
@@ -90,8 +91,11 @@ class RoomChatController extends AsyncNotifier<IList<Event>?> {
           ),
         );
 
+    if (response.events.isEmpty) {
+      state = .data(state.value);
+    } else {
       ref
-        .watch(RoomsController.provider.notifier)
+          .read(RoomsController.provider.notifier)
           .update(
             IMap({
               roomId: Room(
@@ -110,6 +114,7 @@ class RoomChatController extends AsyncNotifier<IList<Event>?> {
             }),
             .new(),
           );
+    }
 
     return response.hasMore;
   }

lib/widgets/room_chat.dart

@@ -80,6 +80,7 @@ class RoomChat extends HookConsumerWidget {
     final controllerData = ref.watch(controllerProvider);
 
     final topEventBeforeLoad = useState<String?>(null);
+    final hasMore = useState<bool>(true);
 
     Future<void> jumpToId(String eventId) async {
       final index = controllerData.value?.indexWhere(
@@ -105,7 +106,7 @@ class RoomChat extends HookConsumerWidget {
     Future<void> loadOlder() async {
       if (controllerData case AsyncData(:final value?)) {
         topEventBeforeLoad.value = value.firstOrNull?.eventId;
-        await notifier.loadOlder();
+        hasMore.value = await notifier.loadOlder();
       }
     }
 
@@ -470,6 +471,7 @@ class RoomChat extends HookConsumerWidget {
                                 ScrollViewKeyboardDismissBehavior.onDrag,
                             controller: scrollController,
                             slivers: [
+                              if (hasMore.value)
                                 SliverToBoxAdapter(
                                   child: Padding(
                                     padding: .symmetric(vertical: 36),