Update README.md

README.md

@@ -20,9 +20,9 @@ concurrency.
 - [x] unbounded concurrency with the `future` primitive
 - [x] asynchronous waiting on `Future` and `Promise` objects
 - [x] mutexes (with asynchronous blocking)
-- [ ] channels (single producer, single consumer)
-- [ ] asynchronous I/O
-- [ ] task cancellation
+- [x] asynchronous I/O (with [liburing](https://github.com/axboe/liburing))
+- [ ] task and I/O cancellation
+- [ ] channels
 
 
 ### `fork`/`sync`, Structured Concurrency