async_t

This library allows for zero-cost compile-time async-traits. This library needs nightly and features generic_associated_types and type_alias_impl_trait to be enabled. Compiling in stable will automatically use dtolnay's async_trait instead.

It supports everything a normal trait would except:

• default async methods
• blanket implementations
• dynamic dispatch

It can also have problems with lifetimes where they have to be specified.

// spawn example

#[async_trait]
trait Spawn {
    // supports self, &self, &mut self and no self
    async fn spawn() -> JoinHandle<()>;
}

#[async_trait]
impl Spawn for Spawner {
    async fn spawn() -> JoinHandle<()> {
        task::spawn(async {
            // ...
        })
    }
}

async fn spawn<T: Spawn>() -> JoinHandle<()> {
    T::spawn().await
}

#[async_trait]
trait Sleeper {
    #[unsend]
    async fn sleep<T>(t: T) -> T;
}

#[async_trait]
impl Sleeper for () {
    #[unsend]
    async fn sleep<T>(t: T) -> T {
        task::sleep(Duration::from_secs(2)).await;
        t
    }
}