Performance: reuse cURL connections
Created by: ewandennis
This PR holds a cURL session open so it can reuse connections. The effect is to amortise connection setup cost across HTTP requests to the same host.
Changes:
- renamed cURL session var
$ch
to$curl_session
- moved
$curl_session
into a static class variable (self::$curl_session
) - Conditionally create
$curl_session
on first use - Remove call to
curl_close()
to enable session reuse - Call
sparkpost_log()
to report on total call time for each request