How to Handle webkit.messageHandlers.appleLogin.postMessage(message) in Flutter (iOS-only) Using flutter_inappwebview?

Question

I am a developer new to Flutter.

I am developing a webview-based app using Flutter. On the webpage, there is a JavaScript snippet like this:

webkit.messageHandlers.appleLogin.postMessage(message);

This code is used to handle Apple login, and it only works on iOS. I am using the flutter_inappwebview plugin in my Flutter app.

I have no idea how to implement this functionality in Flutter. Could someone explain in detail how to handle this Apple login in Flutter using the flutter_inappwebview plugin?

Your detailed explanation would be greatly appreciated. Thank you!