go fmt
The new `go fmt` adds `//go:build` lines (https://golang.org/doc/go1.17#tools). Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
This makes the metrics package more extensible by allowing the default name of `container_id` to be changed by the package caller. Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
dicussed in #3726 Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>