conceptually similar, but a little more complicated because of the extra integration with the Python runtime. A function containing yield is a generator. All generators are asynchronous; when called they return RedirectHandler uses permanent redirects by default. This is because the routing table does not change at runtime and is presumed to be permanent, while redirects found in handlers are likely to be the result of implementation subclass as well as optional keyword arguments to its initializer can be set globally at runtime with configure. By using the constructor as the factory method, the interface looks like a normal

conceptually similar, but a little more complicated because of the extra integration with the Python runtime. A function containing yield is a generator. All generators are asynchronous; when called they return RedirectHandler uses permanent redirects by default. This is because the routing table does not change at runtime and is presumed to be permanent, while redirects found in handlers are likely to be the result of implementation subclass as well as optional keyword arguments to its initializer can be set globally at runtime with configure. By using the constructor as the factory method, the interface looks like a normal

that all use of references should be absolutely safe, with checking performed automatically by the compiler. But I couldn’t resist the temptation to put in a null reference, simply because it was so easy 另一个核心可以做一些完全不相关的工作， 而且这些工作实际上是同时发生的。 当使用 Rust 中的 async 时，我们总是在处理并发。取决于硬件、操作系统和所使用的异步运 行时（async runtime）– 稍后会介绍更多的异步运行时！并发也可能在底层使用了并行。 现在让我们深入理解 Rust 的异步编程实际上是如何工作的！在接下来的章节中，我们将： • 学习如何使用 Rust 的 async crates。futures crate 是 一个 Rust 异步代码试验的官方仓库，也正是 Future 最初设计的地方。Tokio 是目前 Rust 中 应用最广泛的异步运行时（async runtime），特别是 web 应用。这里还有其他优秀的运行时， 它们可能更适合你的需求。我们在 trpl 的底层使用 tokio crate 是因为它经过了充分测试并 被广泛采用。 在一些场景中，trpl