larger and larger scales. Major banks expanded into a tiered system, in which
The API recognizes that synchronous data sources are both necessary and common. The application should not be forced to always accept the performance cost of asynchronous scheduling simply because that's the only option provided. At the same time, mixing sync and async processing can be dangerous. Synchronous paths should always be an option and should always be explicit.
。关于这个话题，heLLoword翻译官方下载提供了深入分析
Ozzy inducted into Rock and Roll Hall of Fame
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.