fix more than needed rebuilds on canvas children

this used a stupid builderFunc instead of a widget so flutter wasn't able to optimise those widget builds and it was simply a blanket rebuild. Added more examples as well

example/lib/main.dart

@@ -1,4 +1,6 @@
 import './app.dart';
+import './caching_test.dart';
+import './dynamic_widget_example.dart';
 import 'package:flutter/material.dart';
 
 void main() {
@@ -6,8 +8,58 @@ void main() {
     MaterialApp(
       // showPerformanceOverlay: true,
       title: 'Infinite Lazy 2D Grid Example',
-      home: const App(),
+      home: const ExampleChooser(),
       debugShowCheckedModeBanner: false,
     ),
   );
 }
+
+class ExampleChooser extends StatelessWidget {
+  const ExampleChooser({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('Infinite Lazy Grid Examples')),
+      body: Center(
+        child: Column(
+          mainAxisAlignment: MainAxisAlignment.center,
+          children: [
+            ElevatedButton(
+              onPressed: () {
+                Navigator.push(context, MaterialPageRoute(builder: (context) => const App()));
+              },
+              child: const Text('Original Example'),
+            ),
+            const SizedBox(height: 16),
+            ElevatedButton(
+              onPressed: () {
+                Navigator.push(context, MaterialPageRoute(builder: (context) => const CachingTestApp()));
+              },
+              child: const Text('Widget Caching Test'),
+            ),
+            const SizedBox(height: 16),
+            ElevatedButton(
+              onPressed: () {
+                Navigator.push(context, MaterialPageRoute(builder: (context) => const DynamicWidgetExample()));
+              },
+              child: const Text('Dynamic Widget Inputs'),
+            ),
+            const SizedBox(height: 32),
+            const Padding(
+              padding: EdgeInsets.all(16.0),
+              child: Text(
+                'Examples:\n'
+                '• Original: Basic usage demo\n'
+                '• Caching Test: Shows Flutter\'s automatic widget optimization\n'
+                '• Dynamic Inputs: How to handle changing widget data',
+                textAlign: TextAlign.center,
+                style: TextStyle(fontSize: 14, color: Colors.grey),
+              ),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}