update example with extension

example/ios/Runner/AppDelegate.swift

@@ -3,11 +3,39 @@ import Flutter
 
 @UIApplicationMain
 @objc class AppDelegate: FlutterAppDelegate {
-  override func application(
-    _ application: UIApplication,
-    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
-  ) -> Bool {
-    GeneratedPluginRegistrant.register(with: self)
-    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
-  }
+    let sharedDefaults = UserDefaults(suiteName: "group.io.stream.flutter")
+    
+    override func application(
+        _ application: UIApplication,
+        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
+    ) -> Bool {
+        if let jsonMessage = sharedDefaults?.stringArray(forKey: "messageQueue") {
+            UserDefaults.standard.setValue(jsonMessage, forKey: "flutter.messageQueue")
+            sharedDefaults?.removeObject(forKey: "messageQueue")
+        }
+
+        GeneratedPluginRegistrant.register(with: self)
+        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
+    }
+    
+    override func applicationDidEnterBackground(_ application: UIApplication) {
+        if let apiKey = UserDefaults.standard.string(forKey: "flutter.KEY_API_KEY") {
+            sharedDefaults?.setValue(apiKey, forKey: "KEY_API_KEY")
+        }
+
+        if let token = UserDefaults.standard.string(forKey: "flutter.KEY_TOKEN") {
+            sharedDefaults?.setValue(token, forKey: "KEY_TOKEN")
+        }
+
+        if let userId = UserDefaults.standard.string(forKey: "flutter.KEY_USER_ID") {
+            sharedDefaults?.setValue(userId, forKey: "KEY_USER_ID")
+        }
+    }
+    
+    override func applicationWillEnterForeground(_ application: UIApplication) {
+        if let jsonMessage = sharedDefaults?.stringArray(forKey: "messageQueue") {
+            UserDefaults.standard.setValue(jsonMessage, forKey: "flutter.messageQueue")
+            sharedDefaults?.removeObject(forKey: "messageQueue")
+        }
+    }
 }

example/ios/Runner/Runner.entitlements

@@ -4,5 +4,9 @@
 <dict>
 	<key>aps-environment</key>
 	<string>development</string>
+	<key>com.apple.security.application-groups</key>
+	<array>
+		<string>group.io.stream.flutter</string>
+	</array>
 </dict>
 </plist>