A secure token that you use to delete a Store and Forward batch.
A `StoreAndForwardBatchDeletionToken` holds the token your payment service provider
supplies when they successfully send a batch of Store and Forward payments for processing.
After receiving the raw token data from your provider, create an instance of this structure and pass it
to the ``PaymentCardReaderStore/resolveBatch(batchDeletionToken:)`` method.
When resolving a Store and Forward batch, the ``PaymentCardReaderStore``
uses this token to verify that the payments were delivered to the payment service
provider and can now be deleted.