title: How to complete in app purchase(subscription) for my flutter app
body: <p>I set up platform in RevenueCat for Subscription and successfully connected with my app. I set up In app purchase in App Store connect. I have a question: Do I have to first submit for review in app purchase, and when App Store approve it , then I can test in sandbox if my implementation of subscription working? I don't understand the order of the steps to be able successfully launch my app with subscription in App Store.
  Or I can test my subscription implementation  before submitting in app purchase ? And once all working then I submit in app purchase for review?</p>