question

When running this in Unity, it says item is not set to an instance of an object. Am I just overlooking something?

void PurchaseItem() {
        ItemPurchaseRequest item = new ItemPurchaseRequest();
        item.ItemId = "10";
        item.Quantity = 1;
        item.Annotation = "Bought from store";


        StartPurchaseRequest purchaseRequest = new PlayFab.ClientModels.StartPurchaseRequest();
        purchaseRequest.Items[0] = item;


        PlayFabClientAPI.StartPurchase(purchaseRequest, (result) => {
            Debug.Log("Object DisplayName: " + result.Contents [4]);
        }, (error) => {


        });
    }