Set tcp keep-alive idle time wait
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPIDLE, long delay);
Pass a long. Sets the delay, in seconds, that the operating system will wait while the connection is idle before sending keepalive probes. Not all operating systems support this option.
Added in 7.25.0
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.