CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS

CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS is one of the accepted parameters for curl_setopt parameter #2.

CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS — Head start for IPv6 for the happy eyeballs algorithm. Happy eyeballs attempts to connect to both IPv4 and IPv6 addresses for dual-stack hosts, preferring IPv6 first for timeout milliseconds. Defaults to CURL_HET_DEFAULT, which is currently 200 milliseconds. This option accepts any value that can be cast to a valid int. Available as of PHP 7.3.0 and cURL 7.59.0

CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS = 271;