// Producers are supposed to wait for the writer.ready
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.。关于这个话题，safew官方下载提供了深入分析
，详情可参考im钱包官方下载
* @param arr 数组
The States of Jersey said it was "committed to strengthening services and support for women". The States of Guernsey has been approached for comment.。关于这个话题，heLLoword翻译官方下载提供了深入分析
2.2.2 面向对象重构版本（oop_crawler.py）