in src/main/scala/com/gu/fastly/api/FastlyApiClient.scala [226:229]
private def statsParams(from: DateTime, to: DateTime, by: By.Value, region: Region.Value = Region.all): Map[String, String] = {
def millis(date: DateTime): String = (date.getMillis / 1000).toString
Map[String, String]("from" -> millis(from), "to" -> millis(to), "by" -> by.toString, "region" -> region.toString)
}