curl --request GET \
  --url https://api-dev.narrative.io/datasets/{dataset_id}/metrics \
  --header 'Authorization: Bearer <token>'

{
  "value": [
    {
      "value": [
        {
          "column_name": "<string>",
          "approx_count_distinct": 123,
          "count_distinct": 123,
          "histogram": {
            "values": {},
            "number_of_bins": 123
          },
          "mean": 123,
          "standard_deviation": 123,
          "completeness": 123,
          "observed_types": {
            "values": {},
            "number_of_bins": 123
          }
        }
      ]
    }
  ]
}