use correct response model

lib/src/channel_name.dart

@@ -12,60 +12,65 @@ class ChannelName extends StatelessWidget {
   /// Instantiate a new ChannelName
   const ChannelName({
     Key key,
-    this.channel,
     this.textStyle,
   }) : super(key: key);
 
-  /// The channel to show the name of
-  final Channel channel;
-
   /// The style of the text displayed
   final TextStyle textStyle;
 
   @override
   Widget build(BuildContext context) {
     final client = StreamChat.of(context);
-    final channel = this.channel ?? StreamChannel.of(context).channel;
+    final channel = StreamChannel.of(context).channel;
+
+    return StreamBuilder<Map<String, dynamic>>(
+      stream: channel.extraDataStream,
+      initialData: channel.extraData,
+      builder: (context, snapshot) {
+        return _buildName(snapshot.data, channel.state.members, client);
+      },
+    );
+  }
+
+  Widget _buildName(
+    Map<String, dynamic> extraData,
+    List<Member> members,
+    StreamChatState client,
+  ) {
     return LayoutBuilder(
       builder: (context, constraints) {
-        return StreamBuilder<Map<String, dynamic>>(
-          stream: channel.extraDataStream,
-          initialData: channel.extraData,
-          builder: (context, snapshot) {
-            String title;
-            if (snapshot.data['name'] == null) {
-              final otherMembers = channel.state.members
-                  .where((member) => member.userId != client.user.id);
-              if (otherMembers.isNotEmpty) {
-                final maxWidth = constraints.maxWidth;
-                final maxChars = maxWidth / textStyle.fontSize;
-                int currentChars = 0;
-                final currentMembers = <Member>[];
-                otherMembers.forEach((element) {
-                  final newLength = currentChars + element.user.name.length;
-                  if (newLength < maxChars) {
-                    currentChars = newLength;
-                    currentMembers.add(element);
-                  }
-                });
-
-                final exceedingMembers =
-                    otherMembers.length - currentMembers.length;
-                title =
-                    '${currentMembers.map((e) => e.user.name).join(', ')} ${exceedingMembers > 0 ? '+ $exceedingMembers' : ''}';
-              } else {
-                title = channel.id;
+        String title;
+        if (extraData['name'] == null) {
+          final otherMembers =
+              members.where((member) => member.userId != client.user.id);
+          if (otherMembers.isNotEmpty) {
+            final maxWidth = constraints.maxWidth;
+            final maxChars = maxWidth / textStyle.fontSize;
+            var currentChars = 0;
+            final currentMembers = <Member>[];
+            otherMembers.forEach((element) {
+              final newLength = currentChars + element.user.name.length;
+              if (newLength < maxChars) {
+                currentChars = newLength;
+                currentMembers.add(element);
               }
-            } else {
-              title = snapshot.data['name'];
-            }
+            });
 
-            return Text(
-              title,
-              style: textStyle,
-              overflow: TextOverflow.ellipsis,
-            );
-          },
+            final exceedingMembers =
+                otherMembers.length - currentMembers.length;
+            title =
+                '${currentMembers.map((e) => e.user.name).join(', ')} ${exceedingMembers > 0 ? '+ $exceedingMembers' : ''}';
+          } else {
+            title = 'No title';
+          }
+        } else {
+          title = extraData['name'];
+        }
+
+        return Text(
+          title,
+          style: textStyle,
+          overflow: TextOverflow.ellipsis,
         );
       },
     );