AsyncStatus Polling

function pollResult($ref, $max = 30) {
    for ($i = 0; $i < $max; $i++) {
        $r = gateway_post('https://secure.cyogate.net/api/cpca/v1/asyncstatus',
                          ['security_key' => KEY, 'transaction_ref' => $ref]);
        if ($r['status'] === 'complete') return $r;
        if ($r['status'] === 'error')    throw new Exception($r['message']);
        sleep(2);
    }
    throw new Exception('Timed out');
}