Revoke Purchase
To implement the Revoke API using the SDK, implement one abstract method from the PurchaseController class: ProcessRevokePurchase.
/// <summary>
/// Processes Revoke Purchases requests.
/// </summary>
/// <returns>A <see cref="Task{T}"/> of <see cref="RevokePurchaseResponse"/> or an exception if bill once purchases are not supported.</returns>
protected override Task<RevokePurchaseResponse> ProcessRevokePurchase(PurchaseRequest purchaseRequest);