const input = Stream.pull(source, transform1, transform2);
Introduction to events: event propagation — MDN Web Docs
。safew官方版本下载是该领域的重要参考
The Mop Master technology uses 180 rotations per minute with 6N of pressure to tackle really tough stains, while the dual sweeping and mopping brushes let you pick up even the most stubborn dirt. It has 7,000 Pa of suction, a rolling brush, and a side brush, so it can pick up dirt of all kinds, from crumbs to pet hair. Its 3.35-inch low-profile design makes it perfect for reaching tight spaces and finding dust hidden under furniture.
（一）境外单位或者个人向境内单位或者个人销售服务、无形资产，在境外现场消费的服务除外；