Merge pull request #247 from Be-ing/closures

intro: async closures exist now!

Author: nrc

src/intro.md

@@ -41,7 +41,7 @@ Like all examples in this book, if you want to see the full example (including `
 
 The async features of Rust have been in development for a while, but it is not a 'finished' part of the language. Async Rust (at least the parts available in the stable compiler and standard libraries) is reliable and performant. It is used in production in some of the most demanding situations at the largest tech companies. However, there are some missing parts and rough edges (rough in the sense of ergonomics rather than reliability). You are likely to stumble upon some of these parts during your journey with async Rust. For most missing parts, there are workarounds and these are covered in this book.
 
-Currently, working with async iterators (also known as streams) is where most users find some rough parts. Some uses of async in traits are not yet well-supported. Async closures don't exist yet, and there is not a good solution for async destruction.
+Currently, working with async iterators (also known as streams) is where most users find some rough parts. Some uses of async in traits are not yet well-supported. There is not a good solution for async destruction.
 
 Async Rust is being actively worked on. If you want to follow development, you can check out the Async Working Group's [home page](https://rust-lang.github.io/wg-async/meetings.html) which includes their [roadmap](https://rust-lang.github.io/wg-async/vision/roadmap.html). Or you could read the async [project goal](https://github.com/rust-lang/rust-project-goals/issues/105) within the Rust Project.