Global Event Manager, how to setup?


#1

https://book.cakephp.org/3.0/en/core-libraries/events.html#global-event-manager

What is $aCallback variable in:

// In any configuration file or piece of code that executes before the event
use Cake\Event\EventManager;

EventManager::instance()->on(
    'Model.Order.afterPlace',
    $aCallback
); 

??

How to create Event class in plugin, and then use?