| e | The purchase details. | 
                  PurchaseProcessingResult
        Applications should only return PurchaseProcessingResult.Complete when a permanent record of the purchase has been made. If PurchaseProcessingResult.Pending is returned Unity IAP will continue to notify the app of the purchase on startup, also via ProcessPurchase.
      
Called when a purchase succeeds.
May be called again at startup for a given purchase if the application previously returned PurchaseProcessingResult.Pending from ProcessPurchase.