s.TTFBAvgDuration = atomic.LoadUint64(&globalStats.tcpTimeForFirstByteTotalDur) / v
	}
	return s
}

// Return a function which update the global stats related to tcp connections
func setupReqStatsUpdate(req *http.Request) (*http.Request, func()) {
	var dialStart, dialEnd int64
	start := time.Now()
	trace := &httptrace.ClientTrace{
		GotFirstResponseByte: func() {