curl --request GET \
  --url https://api.utage-system.com/v1/accounts/{account_id}/scenarios/{scenario_id}/messages/{message_id}/stats \
  --header 'Authorization: Bearer <token>'

{
  "data": {
    "message_id": "<string>",
    "title": "<string>",
    "send_datetime": "<string>",
    "send_count": 123,
    "open_count": 123,
    "open_rate": 123,
    "click_count": 123,
    "click_rate": 123,
    "unsubscribe_count": 123,
    "use_ab_test": true,
    "ab_test_patterns": [
      {
        "subject": "<string>",
        "send_count": 123,
        "open_count": 123,
        "open_rate": 123,
        "click_count": 123,
        "click_rate": 123,
        "unsubscribe_count": 123
      }
    ]
  }
}