public function fork()
    {
        if (!function_exists('pcntl_fork')) {
            return false;
        }
        $pid = pcntl_fork();

        if ($pid == -1) {
            //failure
            return false;
        } elseif ($pid) {
            return true;
        } else {
            $this->start();
            exit(0);
        }
    }