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/data_transfer_page.dart

@@ -60,25 +60,31 @@ class DataTransferPage extends StatelessWidget {
             children: [
               ElevatedButton(
                 style: ElevatedButton.styleFrom(
-                    foregroundColor: (controller.runningTest == 1)
-                        ? Colors.blueAccent
-                        : Colors.blueGrey),
+                  foregroundColor: switch (controller.runningTest) {
+                    1 => Colors.blueAccent,
+                    _ => Colors.blueGrey,
+                  },
+                ),
                 onPressed: () => controller.generateRandomNumbers(false),
                 child: const Text('Transfer Data to 2nd Isolate'),
               ),
               ElevatedButton(
                 style: ElevatedButton.styleFrom(
-                    foregroundColor: (controller.runningTest == 2)
-                        ? Colors.blueAccent
-                        : Colors.blueGrey),
+                  foregroundColor: switch (controller.runningTest) {
+                    2 => Colors.blueAccent,
+                    _ => Colors.blueGrey,
+                  },
+                ),
                 onPressed: () => controller.generateRandomNumbers(true),
                 child: const Text('Transfer Data with TransferableTypedData'),
               ),
               ElevatedButton(
                 style: ElevatedButton.styleFrom(
-                    foregroundColor: (controller.runningTest == 3)
-                        ? Colors.blueAccent
-                        : Colors.blueGrey),
+                  foregroundColor: switch (controller.runningTest) {
+                    3 => Colors.blueAccent,
+                    _ => Colors.blueGrey,
+                  },
+                ),
                 onPressed: controller.generateOnSecondaryIsolate,
                 child: const Text('Generate on 2nd Isolate'),
               ),
@@ -115,19 +121,16 @@ class DataTransferIsolateController extends ChangeNotifier {
 
   void listen() {
     _incomingReceivePort.listen((dynamic message) {
-      if (message is SendPort) {
-        _outgoingSendPort = message;
-      }
-
-      if (message is int) {
-        currentProgress.insert(
-            0, '$message% - ${_timer.elapsedMilliseconds / 1000} seconds');
-        progressPercent = message / 100;
-      }
-
-      if (message is String && message == 'done') {
-        runningTest = 0;
-        _timer.stop();
+      switch (message) {
+        case SendPort():
+          _outgoingSendPort = message;
+        case int():
+          currentProgress.insert(
+              0, '$message% - ${_timer.elapsedMilliseconds / 1000} seconds');
+          progressPercent = message / 100;
+        case 'done':
+          runningTest = 0;
+          _timer.stop();
       }
 
       notifyListeners();

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);
       }
     });
   }

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'));
                   },
                 ),

isolate_example/pubspec.yaml

@@ -4,7 +4,7 @@ version: 1.0.0+1
 publish_to: none
 
 environment:
-  sdk: '>=2.19.5 <4.0.0'
+  sdk: ^3.0.0-0
 
 dependencies:
   flutter: