* The schema and version of telemetry data is exposed through the Content-Type header instead of through a custom HTTP Header. See [Prometheus Client Data Exposition Format][1] for more details. [1]: https://docs.google.com/a/soundcloud.com/document/d/1ZjyKiKxZV83VI9ZKAXRGKaUKK2BIWCT7oiGBKDBpjEY/edit#heading=h.wnviarbnyxcj
WIP - Please review but do not merge.