lightweight alternative to prometheus/client_golang (library)

 This is a lightweight package for exporting metrics in Prometheus format.
 .
 Features:
  * Lightweight. Has minimal number of third-party dependencies and all these
    deps are small.
  * Easy to use.
  * Fast.
  * Allows exporting distinct metric sets via distinct endpoints.
  * Supports easy-to-use histograms, which just work without any tuning.
 .
 Limitations:
  * It doesn't implement advanced functionality from
    github.com/prometheus/client_golang.