Returns a voucher object if the call succeeded for a voucher count of 1 and an
async_action_id if the request was made to create more than 1 voucher.
The returned object will have information about discount type, and discount amount, and all other which you provided to overwrite the origin one from campaign definition.
For the asynchronous action response, it will return the
async_action_id of the scheduled async action. It informs you that your request has been accepted and vouchers will be added to the repository asynchronously. To check the import status and result, copy async action id from the response and pass it to the Get Async Action endpoint.