This HTTP endpoint allows you to request the list of items that belong to a user. These are referred to as item instances. Item instances will only be returned by this method if they have remaining uses, or are unlimited-use items. This should be done after receiving a callback or successful transaction event, as well as each time the game loads in order to check for un-credited items in the inventory.
This call should only be made from a server. To retrieve a user's items from your client, see the requestUserItemList method.