As it stands on the http.go file in the prometheus/client_golang repository, that file has been deprecated and moved to prom/http directory, with some changes. Quoted from http.go comment section:
It is a partial mirror of promhttp/http.go (to avoid circular import chains) where
everything HTTP related should live. The functions here are just for avoiding breakage.
Everything is deprecated.
For this reason, would it be possible to update the prometheus metrics in go-kit to use the new one?