protected function serversDiffer(): bool
    {
        if (!$this->enabled) {
            return false; // Not possible.
        }
        $active_servers = []; // Initialize.

        foreach ($this->Pool->getServerList() as $_server) {
            $active_servers[$_server['host'].':'.$_server['port']] = $_server;
        } // unset($_server); // Housekeeping.

        if (count($this->servers) !== count($active_servers)) {
            return true; // They definitely differ.
        }
        foreach ($this->servers as $_key => $_server) {
            if (!isset($active_servers[$_key])) {
                return true;
            } // unset($_key, $_server);
        }
        foreach ($active_servers as $_key => $_server) {
            if (!isset($this->servers[$_key])) {
                return true;
            } // unset($_key, $_server);
        }
        return false;
    }