src/event/EventManager.php
public function notify() {
        $observersToNotify = array();

        //Check which observers must be update
        foreach ($this->_observers as $observer) {
            if ($this->checkIfObserverMustBeUpdate($observer)) {
                //Add the observers in array to be order for priority
                $observersToNotify[] = $observer;
            }
        }

        //Order the list of observers
        usort($observersToNotify, array($this,'orderObserversForPriority'));

        //Update the observers
        foreach ($observersToNotify as $observer) {
            try {
                $this->updateObserverState($observer);
            } catch (\Exception $e) {
                if ((int)$e->getCode()===600) { //Stop propagation
                    break 1;
                }
            }
        }

    }
public function notify() {
        $observersToNotify = array();

        //Check which observers must be update
        foreach ($this->_observers as $observer) {
            if ($this->checkIfObserverMustBeUpdate($observer)) {
                //Add the observers in array to be order for priority
                $observersToNotify[] = $observer;
            }
        }

        //Order the list of observers
        usort($observersToNotify, array($this,'orderObserversForPriority'));

        //Update the observers
        foreach ($observersToNotify as $observer) {
            try {
                $this->updateObserverState($observer);
            } catch (\Exception $e) {
                if ((int)$e->getCode()===600) { //Stop propagation
                    break 1;
                }
            }
        }

    }
Send a notification to the correct observer