{
  "event": "<unknown>",
  "data": {
    "messageId": "<string>",
    "bouncedAt": "<string>",
    "bounceType": "Permanent",
    "recipients": [
      {
        "emailAddress": "<string>",
        "action": "<string>",
        "status": "<string>",
        "diagnosticCode": "<string>"
      }
    ],
    "emailId": "<string>",
    "bounceSubType": "<string>"
  },
  "attempt": 123,
  "timestamp": 123
}