Persistent CurlShareHandle objects

Hey all, I've got a pull request at https://github.com/php/php-src/pull/15603 that I wanted to bring to your attention. We're interested in being able to reuse curl share handles across requests in mod_php, since we'd expect a performance benefit from not having to redo DNS lookups (in the case of CURL_LOCK_DATA_DNS) or having to re-establish connections (in the case of CURL_LOCK_DATA_CONNECT). I'm not tied to the specific implementation in my PR, though I'll note that I ran into an issue with calling curl_share_setopt with CURL_LOCK_DATA_CONNECT that makes it preferable to be able to initialize the curl share handle once with the share options. I've fixed that issue in https://github.com/curl/curl/pull/14696, but of course that won't be available for most people for quite some time. Thanks! Eric Norris