fixed overwrite on internal copy, DST drift in widget anchors, inline errors without controller and removed dead room lookup

lib/widget/async_actions/async_mixin.dart

@@ -6,6 +6,7 @@ class _AsyncMixin extends StatefulWidget {
   final AsyncErrorBuilder? errorBuilder;
   final void Function(String message)? onError;
   final VoidCallback? onSuccess;
+  final bool showInlineError;
   final Widget Function(BuildContext context, bool busy, VoidCallback? handler)
   builder;
 
@@ -16,6 +17,7 @@ class _AsyncMixin extends StatefulWidget {
     this.errorBuilder,
     this.onError,
     this.onSuccess,
+    this.showInlineError = false,
   });
 
   @override
@@ -73,27 +75,27 @@ class _AsyncMixinState extends State<_AsyncMixin> {
   @override
   Widget build(BuildContext context) {
     final busy = _controller.busy;
-    return widget.builder(
+    final child = widget.builder(
       context,
       busy,
       busy || widget.onPressed == null ? null : _trigger,
     );
+    if (!widget.showInlineError) return child;
+    return _InlineErrorWrapper(controller: _controller, child: child);
   }
 }
 
 class _InlineErrorWrapper extends StatelessWidget {
-  final AsyncActionController? controller;
+  final AsyncActionController controller;
   final Widget child;
   const _InlineErrorWrapper({required this.controller, required this.child});
 
   @override
   Widget build(BuildContext context) {
-    final c = controller;
-    if (c == null) return child;
     return AnimatedBuilder(
-      animation: c,
+      animation: controller,
       builder: (context, _) {
-        final err = c.error;
+        final err = controller.error;
         return Column(
           mainAxisSize: MainAxisSize.min,
           crossAxisAlignment: CrossAxisAlignment.center,