nice overview working

lib/widgets/skip_build_when_covered.dart

@@ -0,0 +1,59 @@
+/// Skips building while another route covers this one, then rebuilds on pop.
+library;
+
+import 'package:flutter/material.dart';
+
+/// Shared observer — register on [MaterialApp.navigatorObservers].
+final RouteObserver<ModalRoute<void>> appRouteObserver =
+    RouteObserver<ModalRoute<void>>();
+
+/// Builds via [builder] only when this route is not covered by a pushed page.
+class SkipBuildWhenCovered extends StatefulWidget {
+  const SkipBuildWhenCovered({
+    super.key,
+    required this.builder,
+    this.placeholder = const SizedBox.expand(),
+  });
+
+  final WidgetBuilder builder;
+  final Widget placeholder;
+
+  @override
+  State<SkipBuildWhenCovered> createState() => _SkipBuildWhenCoveredState();
+}
+
+class _SkipBuildWhenCoveredState extends State<SkipBuildWhenCovered>
+    with RouteAware {
+  var _covered = false;
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    final route = ModalRoute.of(context);
+    if (route is PageRoute) {
+      appRouteObserver.subscribe(this, route);
+    }
+  }
+
+  @override
+  void dispose() {
+    appRouteObserver.unsubscribe(this);
+    super.dispose();
+  }
+
+  @override
+  void didPushNext() {
+    if (!_covered) setState(() => _covered = true);
+  }
+
+  @override
+  void didPopNext() {
+    if (_covered) setState(() => _covered = false);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    if (_covered) return widget.placeholder;
+    return widget.builder(context);
+  }
+}