Update for Flutter 3.10 beta (#1746)

## Pre-launch Checklist

- [x] I read the [Flutter Style Guide] _recently_, and have followed its
advice.
- [x] I signed the [CLA].
- [x] I read the [Contributors Guide].
- [x] I updated/added relevant documentation (doc comments with `///`).
- [ ] All existing and new tests are passing.

---------

Co-authored-by: David Iglesias <ditman@gmail.com>
Co-authored-by: Mark Thompson <2554588+MarkTechson@users.noreply.github.com>
Co-authored-by: John Ryan <ryjohn@google.com>

isolate_example/lib/infinite_process_page.dart

@@ -131,11 +131,12 @@ class InfiniteProcessIsolateController extends ChangeNotifier {
 
   void listen() {
     receivePort.listen((dynamic message) {
-      if (message is SendPort) {
-        newIceSP = message;
-        newIceSP.send(_currentMultiplier);
-      } else if (message is int) {
-        setCurrentResults(message);
+      switch (message) {
+        case SendPort():
+          newIceSP = message;
+          newIceSP.send(_currentMultiplier);
+        case int():
+          setCurrentResults(message);
       }
     });
   }