curl --request POST \
  --url https://api.siit.io/v1/requests/{task_uid}/messages \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "body_text": "<string>",
  "sent_by_uid": "<string>",
  "attachments": [
    null
  ]
}'

{
  "result": {
    "uid": "<string>",
    "body_text": "<string>",
    "event_type": "message",
    "sender_type": "user",
    "sent_by_uid": "<string>",
    "submitted_from": "public_api",
    "attachments": [
      {
        "filename": "<string>",
        "url": "<string>"
      }
    ],
    "created_at": "2023-11-07T05:31:56Z"
  }
}