How to set a custom session id on a SilverStripe site

session.php

<?php
session_destroy();
// Start a new session with the token from the url, this will reinitialize the _SESSION
Session::start('wished-session-id');

// Set the current session connected to the controller with an new instance with the proper _SESSION data
$session = new Session(isset($_SESSION) ? $_SESSION : null);
Controller::curr()->setSession($session);

// Some test that this actually works
$pageviews = 1;
if(Session::get('pageviews')){
	$pageviews += Session::get('pageviews');
}
Session::set('pageviews', $pageviews);
		
// We have to manually save the session, since Director doing it on the wrong instance
Session::save();
return Session::get('pageviews');