public function reloadSlaves($graceful = true)
    {
        $this->output->writeln('<info>Reloading all workers gracefully</info>');

        $this->closeSlaves($graceful, function ($slave) {
            /** @var $slave Slave */

            if ($this->output->isVeryVerbose()) {
                $this->output->writeln(
                    sprintf(
                        'Worker #%d has been closed, reloading.',
                        $slave->getPort()
                    )
                );
            }

            $this->newSlaveInstance($slave->getPort());
        });
    }