public function countWorkers()
    {
        $total = count($this->family);
        $busy = 0;
        $available = 0;
        foreach ($this->family as &$child) {
            switch ($child->status) {
                case ChildProcessContainer::STATUS_ALIVE:
                case ChildProcessContainer::STATUS_READY:
                    $available++;
                    break;
                case ChildProcessContainer::STATUS_BUSY:
                case ChildProcessContainer::STATUS_BUSY_BUT_SLEEPY:
                    $busy++;
                    break;
            }
        }
        return array($total, $available);
    }