A really cool feature landed in HHVM, providing async PHP calls.
While your https call is busy sitting on its hands waiting for a response, there’s no reason you shouldn’t be able to do other things, maybe even fire off more requests. The same goes for database queries, which can take just as long, or even filesystem access which is faster than network, but can still introduce lag times of several milliseconds, and those all add up!
But, HHVM isn’t PHP. And PHP has no such feature yet, but it may come to PHP7 when PHP’s IO multiplexing is revamped. So for now, we’re left with workarounds like ReactPHP, background forking of requests, curl_multi_exec() shenanigans and running worker-queues like Gearman.
Sure it gets the job done, but native async looks pretty damn cool.