performance fixes

packages/stream_chat_flutter_core/lib/src/better_stream_builder.dart

@@ -25,29 +25,31 @@ class BetterStreamBuilder<T> extends StatefulWidget {
 }
 
 class _BetterStreamBuilderState<T> extends State<BetterStreamBuilder<T>> {
-  Widget? _child;
   T? _lastEvent;
   StreamSubscription? _subscription;
   Object? _lastError;
 
   @override
-  Widget build(BuildContext context) => _child ?? const Offstage();
+  Widget build(BuildContext context) {
+    if (_lastError != null) {
+      return widget.errorBuilder!(context, _lastError!);
+    }
+
+    if (_lastEvent == null) {
+      return widget.loadingBuilder?.call(context) ?? const Offstage();
+    }
+    return widget.builder(context, _lastEvent ?? widget.initialData);
+  }
 
   bool _firstTime = true;
   @override
   void didChangeDependencies() {
     if (_firstTime) {
-      if (widget.initialData == null && widget.loadingBuilder != null) {
-        _child = widget.loadingBuilder!(context);
-      } else {
-        _onEvent(widget.initialData);
-      }
       _lastEvent = widget.initialData;
       _subscription = widget.stream?.listen(
         _onEvent,
         onError: _onError,
       );
-
       _firstTime = false;
     }
     super.didChangeDependencies();
@@ -55,12 +57,6 @@ class _BetterStreamBuilderState<T> extends State<BetterStreamBuilder<T>> {
 
   @override
   void didUpdateWidget(covariant BetterStreamBuilder<T> oldWidget) {
-    if (_lastError != null && oldWidget.errorBuilder != widget.errorBuilder) {
-      _onError(_lastError);
-    } else if (oldWidget.builder != widget.builder) {
-      _onEvent(_lastEvent);
-    }
-
     if (oldWidget.stream != widget.stream) {
       _subscription?.cancel();
       _subscription = widget.stream?.listen(
@@ -79,21 +75,22 @@ class _BetterStreamBuilderState<T> extends State<BetterStreamBuilder<T>> {
 
   void _onError(error) {
     if (widget.errorBuilder != null && error != _lastError) {
-      setState(() {
-        _child = widget.errorBuilder!(context, error);
-      });
+      if (mounted) {
+        setState(() {});
+      }
       _lastError = error;
     }
   }
 
-  void _onEvent(event) {
+  void _onEvent(T event) {
     _lastError = null;
-    if (widget.comparator != null
+    final isEqual = widget.comparator != null
         ? widget.comparator!(_lastEvent, event)
-        : event != _lastEvent) {
-      setState(() {
-        _child = widget.builder(context, event);
-      });
+        : event == _lastEvent;
+    if (!isEqual) {
+      if (mounted) {
+        setState(() {});
+      }
       _lastEvent = event;
     }
   }

packages/stream_chat_flutter_core/lib/src/stream_channel.dart

@@ -346,36 +346,40 @@ class StreamChannelState extends State<StreamChannel> {
 
   @override
   Widget build(BuildContext context) {
-    Widget child = FutureBuilder<List<bool>>(
-      future: Future.wait(_futures),
-      initialData: [
-        channel.state != null,
-        if (initialMessageId != null) false,
-      ],
-      builder: (context, snapshot) {
-        if (snapshot.hasError) {
-          var message = snapshot.error.toString();
-          if (snapshot.error is DioError) {
-            final dioError = snapshot.error as DioError?;
-            if (dioError?.type == DioErrorType.response) {
-              message = dioError!.message;
-            } else {
-              message = 'Check your connection and retry';
+    var child = widget.child;
+    if (widget.showLoading &&
+        (initialMessageId != null || channel.state == null)) {
+      child = FutureBuilder<List<bool>>(
+        future: Future.wait(_futures),
+        initialData: [
+          channel.state != null,
+          if (initialMessageId != null) false,
+        ],
+        builder: (context, snapshot) {
+          if (snapshot.hasError) {
+            var message = snapshot.error.toString();
+            if (snapshot.error is DioError) {
+              final dioError = snapshot.error as DioError?;
+              if (dioError?.type == DioErrorType.response) {
+                message = dioError!.message;
+              } else {
+                message = 'Check your connection and retry';
+              }
             }
+            return Center(child: Text(message));
           }
-          return Center(child: Text(message));
-        }
-        final initialized = snapshot.data![0];
-        // ignore: avoid_bool_literals_in_conditional_expressions
-        final dataLoaded = initialMessageId == null ? true : snapshot.data![1];
-        if (widget.showLoading && (!initialized || !dataLoaded)) {
-          return const Center(
-            child: CircularProgressIndicator(),
-          );
-        }
-        return widget.child;
-      },
-    );
+          final initialized = snapshot.data![0];
+          final dataLoaded = initialMessageId == null || snapshot.data![1];
+          if (!initialized || !dataLoaded) {
+            return const Center(
+              child: CircularProgressIndicator(),
+            );
+          }
+          return widget.child;
+        },
+      );
+    }
+
     if (initialMessageId != null) {
       child = Material(child: child);
     }