I want an App Store record of the fact that the user flipped a switch in the UI and confirmed it. This is to begin a free trial period for enhanced features in my app. Then the user can actually buy the features later, based on a regular in-app purchase. I see pieces of this described in the documentation, but I don't see how to make this painless for my user: just flip the switch, confirm the dialog, and go, without having to actually present an offer code to some UI. Is this possible? Or is there a better way to implement this?