My question is simply,

1. I have integrated OneSignal Flutter plugin version 5.1.2 in my Flutter app.
2. I have read from the docs that I can get the notification data whenever a user clicks on the notification while the app is opened using this code:

  void _setNotificationClickListener() {
    OneSignal.Notifications.addClickListener((OSNotificationClickEvent event) {
      log('Notification clicked');
      print('NOTIFICATION CLICK LISTENER CALLED WITH EVENT: ${event.jsonRepresentation()}');
    });
  }

3. I want to implement deeplinks into my app, for example:
   Whenever the user clicks on the notification while the app was closed, the app should open up and load the corresponding article for which the notification was sent
4. In this scenario I have the code ready for:
   a. I have a global router which can load the correct article
   b. I’m already sending additional data in the notification from onesignal in my backend

My only problem is how do I get the additional data in code when the app was freshly opened via the notification?