err error
}

// requestGOAWAYServer request test GOAWAY server using specified method and data according to the given url.
// A non-nil channel will be returned if the request is watch, and a watchResponse can be got from the channel when watch done.
func requestGOAWAYServer(client *http.Client, serverBaseURL, url string) (<-chan watchResponse, error) {
	method := http.MethodGet