This came for free with the php-queue library. The remaining work is to make sure we aren't hobbled by any STOMP assumptions in the calling code. Headers vs body might be a big deal.
Parallel to the STOMP implementation. If it helps, we can wrap the MediaWiki cache interface. See extras/custom_filters/filters/ip_velocity/ip_velocity.body.php for existing globals.
Make sure any data we add will expire.