chore: add islate example

Author: medz

example/README.md

@@ -39,3 +39,7 @@ Future<void> main() async {
 }
 
 ```
+
+## Other
+
+- [Using Isolate](isolate.dart)

example/isolate.dart

@@ -0,0 +1,25 @@
+import 'dart:io';
+import 'dart:isolate';
+
+import 'package:spry/spry.dart';
+
+Future<void> runServer([_]) async {
+  final app = createSpry();
+
+  app.get('/', (_) {});
+  app.post('/user', (_) {});
+  app.get('/user/:name', (event) => event.params['name']);
+
+  final server = app.serve(hostname: '0.0.0.0', port: 3000, reusePort: true);
+  await server.ready();
+}
+
+Future<void> main() async {
+  // Run main server.
+  await runServer();
+
+  // Run cluster servers.
+  for (int i = Platform.numberOfProcessors - 1; i > 0; i--) {
+    await Isolate.spawn(runServer, null);
+  }
+}