foo.php

<?php

require __DIR__ . '/vendor/autoload.php';

use \Zend\EventManager\ListenerAggregateInterface;
use \Zend\EventManager\EventManagerInterface;

class Listener implements ListenerAggregateInterface
{
    protected $bigService;

    public function attach(EventManagerInterface $events)
    {
        $events->attach('foo', array($this, 'listen'));
    }

    public function detach(EventManagerInterface $events) {}

    public function listen()
    {
        $bigService = $this->getBigService();
        // do something
    }

    public function getBigService()
    {
        return $this->bigService;
    }

    public function setBigService($bigService)
    {
        $this->bigService = $bigService;
    }
}

$proxy = new \ProxyManager\Factory\LazyLoadingGhostFactory();
$listener = $proxy->createProxy('Listener', function ($proxy, $method, $parameters, & $initializer) {
    if ($method == 'getBigService') {
        $proxy->setBigService(bigService());
    }
});

$memory = memory_get_usage();

$eventManager = new \Zend\EventManager\EventManager();
$eventManager->attach($listener);

$memory = memory_get_usage() - $memory;

var_dump(round($memory/1000000, 2) . 'MB');

function bigService()
{
    $s = array();
    for ($i = 0; $i < 10000; $i++) {
        $s[] = str_repeat('123456789', 200);
    }

    return $s;
}