No FrameHandler in WinUI for now... its too complex and broken

Toolkit.WinUI/TemplatePage.xaml.cs

@@ -0,0 +1,8 @@
+using Microsoft.UI.Xaml.Controls;
+
+namespace Toolkit.WinUI;
+
+public sealed partial class TemplatePage : Page
+{
+    public TemplatePage() => InitializeComponent();
+}