Blue: One thing led to another
"We've also got these big tanks full of oxygen and nitrogen, which are mixed to make air, and also water, so that we can provide everything that the astronauts need in the crew module to keep them alive on their journey."。关于这个话题，WPS下载最新地址提供了深入分析
Transforms don't execute until the consumer pulls. There's no eager evaluation, no hidden buffering. Data flows on-demand from source, through transforms, to the consumer. If you stop iterating, processing stops.，这一点在同城约会中也有详细论述
（应受访者要求，刘成、兰丽为化名）