A VoucherPurchase is the purchase-side record of a voucher
transaction — it captures the buyer, the recipient's contact
details, the delivery method, and the gift-email content. The
tradable VoucherCodes issued by the purchase are managed under
the VoucherCodes tag.
Renders the gift email that would be sent to a voucher recipient
without dispatching it. Use this in operator UIs to show staff
exactly what the recipient will see — including the rendered HTML
body, sender, subject and CC/BCC list — before they commit to
sending.
Pass recipient overrides in the body to preview against a
different address (for example, a staff test inbox).
Sends the gift email to the recipient on file for a voucher
purchase. The rendered email is also returned in the response so
operator UIs can preview what was sent.
Pass recipient overrides in the body to redirect the send — most
commonly when the original delivery bounced or the customer
supplied a corrected email address.