apprt/embedded: ignore size callbacks that change nothing

src/apprt/embedded.zig

@@ -206,6 +206,12 @@ pub const Surface = struct {
     }
 
     pub fn updateSize(self: *Surface, width: u32, height: u32) void {
+        // Runtimes sometimes generate superflous resize events even
+        // if the size did not actually change (SwiftUI). We check
+        // that the size actually changed from what we last recorded
+        // since resizes are expensive.
+        if (self.size.width == width and self.size.height == height) return;
+
         self.size = .{
             .width = width,
             .height = height,