let closed = false;
Backpressure – the ability for a slow consumer to signal a fast producer to slow down – is a first-class concept in Web streams. In theory. In practice, the model has some serious flaws.，这一点在旺商聊官方下载中也有详细论述
。关于这个话题，旺商聊官方下载提供了深入分析
FT Professional，详情可参考一键获取谷歌浏览器下载
storage.save(item)