{
  "adUnits": [
    {
      "auId": "some_au_id",
      "targetId": "some_au_id-imp_id",
      "dimensions": [
        [
          300,
          250
        ]
      ]
    }
  ],
  "metaData": {
    "usi": "user_d"
  },
  "context": "some_page"
}
