$factory = new \ProxyManager\Factory\LazyLoadingValueHolderFactory();

$proxy = $factory->createProxy(
    'MyApp\HeavyComplexObject',
    function (& $wrappedObject, $proxy, $method, $parameters, & $initializer) {
        $wrappedObject = new HeavyComplexObject(); // instantiation logic here
        $initializer   = null; // turning off further lazy initialization
    }
);

$proxy->doFoo();