CURLINFO_PRETRANSFER_TIME man page
CURLINFO_PRETRANSFER_TIME — get the time until the file transfer start
CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_PRETRANSFER_TIME, double *timep);
Pass a pointer to a double to receive the time, in seconds, it took from the start until the file transfer is just about to begin. This includes all pre-transfer commands and negotiations that are specific to the particular protocol(s) involved. It does not involve the sending of the protocol- specific request that triggers a transfer.
See also the TIMES overview in the curl_easy_getinfo(3) man page.
Added in 7.4.1
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
curl_easy_getinfo(3), CURLINFO_APPCONNECT_TIME(3), CURLINFO_STARTTRANSFER_TIME(3).