Merge branch 'master' into feature/new-ui

packages/stream_chat_flutter/example/lib/tutorial-part-3.dart

@@ -63,7 +63,7 @@ class ChannelListPage extends StatelessWidget {
             }
           },
           channelPreviewBuilder: _channelPreviewBuilder,
-          sort: [SortOption('last_message_at')],
+          // sort: [SortOption('last_message_at')],
           pagination: PaginationParams(
             limit: 20,
           ),
@@ -74,8 +74,10 @@ class ChannelListPage extends StatelessWidget {
   }
 
   Widget _channelPreviewBuilder(BuildContext context, Channel channel) {
-    final lastMessage = channel.state.messages.reversed
-        .firstWhere((message) => !message.isDeleted);
+    final lastMessage = channel.state.messages.reversed.firstWhere(
+      (message) => !message.isDeleted,
+      orElse: () => null,
+    );
 
     final subtitle = (lastMessage == null ? 'nothing yet' : lastMessage.text);
     final opacity = channel.state.unreadCount > .0 ? 1.0 : 0.5;