Asynchronous Rust

The async Rust functions, async fn f() {}, are supported as well. Just write normal Rust code, and flutter_rust_bridge code generator will recognize it is async and generate proper bindings. Under the hood, async runtime is utilized to run those functions.

As for when to use asynchronous vs synchronous Rust, there are already many articles on the Internet, for example, by searching "Rust async vs thread pool", "why async Rust", etc. In short, for example, when you want Rust to read/write files, do network requests, etc, it is better to use async. On the other hand, if your computation is CPU-heavy, the thread pool may fit better.

Example

Well, just write anything you like, so here is a bare minimal example:

async fn f() { ... }

With Dart:

await f();

Customization

Similar to how you customize thread pools for synchronous Rust, we can also provide arbitrary async-runtime implementations. This can be done similarly by creating your custom handler instance with custom async runtime.

For example, you may want to change the number of OS threads that Tokio creates. Or, it is also easy to plug in whatever async runtime that you like, by implementing the simple trait BaseAsyncRuntime with a single spawn method.