public function getStatusSummary()
    {
        $map = [
            'total' => Slave::ANY,
            'ready' => Slave::READY,
            'busy' => Slave::BUSY,
            'created' => Slave::CREATED,
            'registered' => Slave::REGISTERED,
            'closed' => Slave::CLOSED
        ];

        return array_map(function ($state) {
            return count($this->getByStatus($state));
        }, $map);
    }