Note: I think PHP is way under appreciated.
2. Officially supported runtime that exposes system event loop to userland (yes, we have swoole and roadrunner)
EDIT: have you looked at ngx-php. It’s blazing fast and provides you that event loop.
That's something up for debate. Personally, I'd like the shared-nothing approach but I'd like to have async capabilities to optimize I/O and a function that flushes the request and frees up resources for next request in queue.
edit: I haven't seen ngx_php, thanks for the link!