Webhook for Chat

Hi,
I have used zendesk mobile SDK's in Flutter using method channels to integrate the native SDK's. Everything is working great 👍  in terms of the chat experience. Now I wanted to integrate the push notification so that the users could get notified when a new message arrives. For android it was pretty easy to do it by using the FCM token which I generate in the flutter code and pass to native android via method channel. But for iOS the process in bit complex for me to make it work with Flutter. I was wondering if anyone was able to make push notification work for iOS using Flutter? If not is there any Webhook for the Chat Service I could use to trigger the notification from our backend using our existing notification management system? Any help is much appreciated.

Thank you.