RootCAs:            globalRootCAs,
			ClientSessionCache: tls.NewLRUClientSessionCache(tlsClientSessionCacheSize),
		},
		DisableCompression: true,
	}
	return updateTransport
}

func getLatestReleaseTime(u *url.URL, timeout time.Duration, mode string) (sha256Sum []byte, releaseTime time.Time, err error) {
	data, err := downloadReleaseURL(u, timeout, mode)
	if err != nil {
		return sha256Sum, releaseTime, err
	}