https://github.com/etcd-io/etcd/blob/616592d9ba993e3fe9798eef581316016df98906/clientv3/integration/util.go#L27-L35
https://github.com/etcd-io/etcd/blob/616592d9ba993e3fe9798eef581316016df98906/pkg/ioutil/reader.go#L22-L27
