curl --request GET \
  --url https://api.utage-system.com/v1/accounts/{account_id}/scenarios/{scenario_id}/messages/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
        }
      ]
    }
  ],
  "meta": {
    "current_page": 123,
    "per_page": 123,
    "total": 123
  }
}