Docs only mention libevent for better performance
ReactPHP will [also utilize the `ev` or `event` extensions](https://github.com/reactphp/event-loop/blob/626faeb9e2c1dfb17b55658676bf3ff580d43d02/src/Factory.php#L7) if they are present. This should be mentioned [in the docs](http://socketo.me/docs/deploy#libevent).