private function _getFastLifetime($lifetime, $priority, $maxLifetime = null)
    {
        if ($lifetime <= 0) {
            // if no lifetime, we have an infinite lifetime
            // we need to use arbitrary lifetimes
            $fastLifetime = (int) (2592000 / (11 - $priority));
        } else {
            // prevent computed infinite lifetime (0) by ceil
            $fastLifetime = (int) ceil($lifetime / (11 - $priority));
        }

        if ($maxLifetime >= 0 && $fastLifetime > $maxLifetime) {
            return $maxLifetime;
        }

        return $fastLifetime;
    }