buildid

var Writer = sync.OnceValue(func() string {
	info, ok := debug.ReadBuildInfo()
	revision, modified := "", false
	if ok {
		for _, s := range info.Settings {
			switch s.Key {
			case "vcs.revision":
				revision = s.Value
			case "vcs.modified":
				modified = s.Value == "true"
			}
		}
	}
	if ok && revision != "" && !modified {
		return info.Main.Version + "+" + revision
	}
	if exe, err := os.Executable(); err == nil {
		if st, err := os.Stat(exe); err == nil {
			return fmt.Sprintf("local+%d+%d", st.Size(), st.ModTime().UnixNano())
		}
	}
	return "unknown"
})