// return user-agent which may be truncated.
type lazyTruncatedUserAgent struct {
	req *http.Request
}

func (lazy *lazyTruncatedUserAgent) String() string {
	ua := "unknown"
	if lazy.req != nil {
		ua = utilnet.GetHTTPClient(lazy.req)
		if len(ua) > maxUserAgentLength {
			ua = ua[:maxUserAgentLength] + userAgentTruncateSuffix
		}
	}
	return ua
}

// LazyClientIP implements String() string and it will