protected function addServer(string $type, Server $server)
    {
        switch ($type) {
            case 'master':
                $this->servers['master'] = ['server' => $server, 'connection' => null];

                break;
            default:
                $serverHashId = spl_object_hash($server);

                if (!isset($this->servers[$type][$serverHashId])) {
                    $this->servers[$type][$serverHashId] = ['server' => $server, 'connection' => null];
                }

                break;
        }
    }