// if the client requests it.
	defaultGzipThresholdBytes = 128 * 1024
)

// negotiateContentEncoding returns a supported client-requested content encoding for the
// provided request. It will return the empty string if no supported content encoding was
// found or if response compression is disabled.
func negotiateContentEncoding(req *http.Request) string {
	encoding := req.Header.Get("Accept-Encoding")
	if len(encoding) == 0 {