{
  "event": "<any>",
  "data": {
    "emailId": "<string>",
    "messageId": "<string>",
    "deliveredAt": "<string>",
    "recipients": [
      "<string>"
    ],
    "remoteMtaIp": "<string>",
    "smtpResponse": "<string>",
    "processingTimeMs": 123
  },
  "attempt": 123,
  "timestamp": 123
}