kubernetes/vendor/go.etcd.io/etcd/pkg/v3/httputil/httputil.go

// GracefulClose drains http.Response.Body until it hits EOF
// and closes it. This prevents TCP/TLS connections from closing,
// therefore available for reuse.
// Borrowed from golang/net/context/ctxhttp/cancelreq.go.
func GracefulClose(resp *http.Response) { … }

// GetHostname returns the hostname from request Host field.
// It returns empty string, if Host field contains invalid
// value (e.g. "localhost:::" with too many colons).
func GetHostname(req *http.Request) string { … }