The real task system
实用任务系统
We've worked through toy definitions of a number of components in this chapter,
but now it's time to get acquainted with the more efficient and powerful
abstractions that are part of the futures crate.
在这一章前面的部分, 我们已经完成了一系列组件的简单定义, 现在是时候让我们来理解
更加有效和强大的抽象方式. 这些抽象已经整合到了futures库中.