kubernetes/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/urlpick.go

type urlPicker …

func newURLPicker(urls types.URLs) *urlPicker { … }

func (p *urlPicker) update(urls types.URLs) { … }

func (p *urlPicker) pick() url.URL { … }

// unreachable notices the picker that the given url is unreachable,
// and it should use other possible urls.
func (p *urlPicker) unreachable(u url.URL) { … }