ConstReadonlydeliveryStatus: "delivery_status"A NOTIFY_WEBHOOK delivery carrying the status of an SMTP delivery.
The SMTP producer does not send an event_type field, so this value is
assigned by decode.
ReadonlyinboundEmail: "inbound_email"A DELIVER_WEBHOOK delivery carrying a complete inbound message.
ReadonlystorageStatus: "s3_egress_status"A NOTIFY_WEBHOOK delivery carrying the status of an object-storage write.
Identifies the shape of a decoded webhook payload.