Serialize PHP data like a PHP session

session_serialize.php

<?php
function session_serialize(array $data) {
    $temp = $_SESSION;
    $_SESSION = $data;
    $out = session_encode();
    $_SESSION = $temp;
    return $out;
}

function session_unserialize($data) {
    $temp = $_SESSION;
    session_decode($data);
    $out = $_SESSION;
    $_SESSION = $temp;
    return $out;
}

This requires you start php session using session_start. How do you serialize/unserialize without starting a session? I need to make it work with a Laravel application here which does not use native php sessions.