public function reload($block = true)
    {
        $old_processes = $this->processes;
        for ($i = 0; $i < $this->max; $i++) {
            $process = new Process($this->runnable);
            $process->start();
            $this->processes[$process->getPid()] = $process;
        }

        foreach ($old_processes as $process) {
            $process->shutdown();
            $process->wait($block);
            unset($this->processes[$process->getPid()]);
        }
    }