Logout, too.

<?php
include "OSRFGatewayClient.php";

$client = new OSRFGatewayClient("jammy.cwmars.org");
$request = new OSRFRequest("open-ils.auth", "open-ils.auth.session.delete",
"c723db268bbfaa4cd923c354b1f41f48");
$response = $client->request($request);
print_r($response);
EOF
stdClass Object
(
    [payload] => Array
        (
            [0] => c723db268bbfaa4cd923c354b1f41f48
        )

    [status] => 200
)