Merge pull request #429 from GetStream/perf-fixes

fix: performance

packages/stream_chat/example/lib/main.dart

@@ -79,21 +79,21 @@ class HomeScreen extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final messages = channel.state!.channelStateStream;
+    final messages = channel.state!.messagesStream;
     return Scaffold(
       appBar: AppBar(
         title: Text('Channel: ${channel.id}'),
       ),
       body: SafeArea(
-        child: StreamBuilder<ChannelState?>(
+        child: StreamBuilder<List<Message>?>(
           stream: messages,
           builder: (
             BuildContext context,
-            AsyncSnapshot<ChannelState?> snapshot,
+            AsyncSnapshot<List<Message>?> snapshot,
           ) {
             if (snapshot.hasData && snapshot.data != null) {
               return MessageView(
-                messages: snapshot.data!.messages.reversed.toList(),
+                messages: snapshot.data!.reversed.toList(),
                 channel: channel,
               );
             } else if (snapshot.hasError) {

packages/stream_chat/lib/src/api/channel.dart

@@ -2,7 +2,8 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:math';
 
-import 'package:collection/collection.dart' show IterableExtension;
+import 'package:collection/collection.dart'
+    show IterableExtension, ListEquality;
 import 'package:dio/dio.dart';
 import 'package:logging/logging.dart';
 import 'package:rxdart/rxdart.dart';
@@ -1601,8 +1602,9 @@ class ChannelClientState {
   List<Message> get messages => _channelState.messages;
 
   /// Channel message list as a stream
-  Stream<List<Message>?> get messagesStream =>
-      channelStateStream.map((cs) => cs.messages);
+  Stream<List<Message>?> get messagesStream => channelStateStream
+      .map((cs) => cs.messages)
+      .distinct((prev, next) => const ListEquality().equals(prev, next));
 
   /// Channel pinned message list
   List<Message>? get pinnedMessages => _channelState.pinnedMessages.toList();