无需等待即可运行异步Process

Question

我有以下命令运行Symfony2进程：

class UpdateShopsCommand extends Command
{
    protected function configure()
    {
        $this
            ->setName('backgroundtask:updateshop')
            ->setDescription('Update paying shops pictures and bio')
        ;
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $container = $this->getApplication()->getKernel()->getContainer();
        $shopsNeededToBeUpdated = $this->getShopsNeedToBeUpdated();
        foreach ($shopsNeededToBeUpdated as $shop) {
            //start a process here
            var_dump('updating shop ' . $shop->getUsername());
            $process = new Process('app/console backgroundtask:refreshuserinfo ' . $shop->getUserid() . ' false --env=' . $this->get('kernel')->getEnvironment());
            $process->setTimeout(3600);
            $process->start();
            $process->wait(function ($type, $buffer) {
                if (Process::ERR === $type) {
                    echo 'ERR > '.$buffer;
                } else {
                    echo 'OUT > '.$buffer;
                }
            });
        }

        $output->writeln('Finished updating shops');
    }
}

如果我有等待功能，代码就能完美运行。但是我不希望其中包含wait，因为等待阻塞线程，现在它不是异步，只是想启动进程异步。但是，当我这样做时，就好像这个过程从未开始过。为什么是这样？我真的需要等待异步过程吗？我怎么知道它实际上正在运行？