feat: cross platform projects.

demo/Ursa.Demo.iOS/AppDelegate.cs

@@ -0,0 +1,23 @@
+using Foundation;
+using UIKit;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.iOS;
+using Avalonia.Media;
+using Avalonia.ReactiveUI;
+
+namespace Ursa.Demo.iOS;
+
+// The UIApplicationDelegate for the application. This class is responsible for launching the 
+// User Interface of the application, as well as listening (and optionally responding) to 
+// application events from iOS.
+[Register("AppDelegate")]
+public partial class AppDelegate : AvaloniaAppDelegate<App>
+{
+    protected override AppBuilder CustomizeAppBuilder(AppBuilder builder)
+    {
+        return base.CustomizeAppBuilder(builder)
+            .WithInterFont()
+            .UseReactiveUI();
+    }
+}