switch method {
	case "GET", "HEAD", "DELETE", "OPTIONS", "PROPFIND", "SEARCH":
		return true
	}
	return false
}

// requiresHTTP1 reports whether this request requires being sent on
// an HTTP/1 connection.
func (r *Request) requiresHTTP1() bool {
	return hasToken(r.Header.Get("Connection"), "upgrade") &&
		ascii.EqualFold(r.Header.Get("Upgrade"), "websocket")

// with Transport.RegisterProtocol) should be respected for this request.
func (t *Transport) useRegisteredProtocol(req *Request) bool {
	if req.URL.Scheme == "https" && req.requiresHTTP1() {
		// If this request requires HTTP/1, don't use the
		// "https" alternate protocol, which is used by the
		// HTTP/2 code to take over requests if there's an
		// existing cached HTTP/2 connection.
		return false