curl --request POST \
  --url https://api.nuvia.ai/v1/messages/send-audio \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "conversationId": "<string>",
  "message": {
    "content": "<string>",
    "attachment": "<string>",
    "contentAttributes": {
      "inReplyToExternalId": "<string>"
    }
  }
}
'

{
  "content": "<string>",
  "conversation": "<unknown>",
  "inbox": "<unknown>",
  "contact": "<unknown>",
  "company": "<unknown>",
  "_id": "<string>",
  "additional_attributes": "<unknown>",
  "source_id": "<string>",
  "user": "<unknown>",
  "attachments": [
    "<unknown>"
  ],
  "errors": [
    {
      "code": "<string>",
      "title": "<string>",
      "message": "<string>"
    }
  ],
  "createdAt": "<unknown>",
  "updatedAt": "<unknown>"
}