Add Priority for Symfony Event Listeners

Code
<?php

use Symfony\Component\EventDispatcher\EventDispatcher;
use 
Symfony\Component\EventDispatcher\Event;

// event listeners
$eventListener1 = function (Event $event) {
    echo 
'Call me' PHP_EOL;
};

$eventListener2 = function (Event $event) {
    echo 
'Call me too' PHP_EOL;
};

// add listeners to EventDispatcher
$dispatcher = new EventDispatcher();
$dispatcher->addListener('callme'$eventListener12);
$dispatcher->addListener('callme'$eventListener23);

// priority of "callme" event
dump($dispatcher->getListenerPriority('callme'$eventListener2));

$dispatcher->dispatch('callme', new Event());
Result
3

Call me too
Call me
Used Versions
PHP 7.1, Zend 3.0, Symfony 3.2, Laravel 5.2, PHPUnit 5.6, Doctrine 2.6