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/performance_page.dart

@@ -56,10 +56,11 @@ class _PerformancePageState extends State<PerformancePage> {
                   builder: (context, snapshot) {
                     return ElevatedButton(
                       style: ElevatedButton.styleFrom(elevation: 8.0),
-                      onPressed:
-                          snapshot.connectionState == ConnectionState.done
-                              ? () => handleComputeOnMain(context)
-                              : null,
+                      onPressed: switch (snapshot.connectionState) {
+                        ConnectionState.done => () =>
+                            handleComputeOnMain(context),
+                        _ => null
+                      },
                       child: const Text('Compute on Main'),
                     );
                   },
@@ -69,10 +70,11 @@ class _PerformancePageState extends State<PerformancePage> {
                   builder: (context, snapshot) {
                     return ElevatedButton(
                         style: ElevatedButton.styleFrom(elevation: 8.0),
-                        onPressed:
-                            snapshot.connectionState == ConnectionState.done
-                                ? () => handleComputeOnSecondary(context)
-                                : null,
+                        onPressed: switch (snapshot.connectionState) {
+                          ConnectionState.done => () =>
+                              handleComputeOnSecondary(context),
+                          _ => null
+                        },
                         child: const Text('Compute on Secondary'));
                   },
                 ),