void Curl_pgrsTimeWas(struct Curl_easy *data, timerid timer,
                      struct curltime timestamp)
{
  timediff_t *delta = NULL;

  switch(timer) {
…
  case TIMER_NAMELOOKUP:
    delta = &data->progress.total.nslookup_us;
    break;
  case TIMER_CONNECT:
    delta = &data->progress.total.connect_us;
    break;
  case TIMER_APPCONNECT:
    delta = &data->progress.total.appconnect_us;
    break;
  case TIMER_PRETRANSFER:
    delta = &data->progress.total.pretransfer_us;
    break;
  case TIMER_STARTTRANSFER:
    /* prevent updating t_starttransfer unless:
     *   1. this is the first time we are setting t_starttransfer
     *   2. a redirect has occurred since the last time t_starttransfer was set
     * This prevents repeated invocations of the function from incorrectly
     * changing the t_starttransfer time.
     */
    if(data->progress.startransfer_added) {
      CURL_TRC_M(data, "[%s] ignored", pgrs_timer_name(timer));
      return;
    }
    data->progress.startransfer_added = TRUE;
    delta = &data->progress.total.starttransfer_us;
    break;
…
  if(delta) {
    timediff_t us = curlx_ptimediff_us(&timestamp, &data->progress.start) -
                    data->progress.delta.startsingle_us;
    if(us < 1)
      us = 1; /* make sure at least one microsecond passed */
    *delta += us;

Warm-up