Comment by WhyNotHugo

Here's a nice example of a Trait that has async functions:

    fn list_items<'life0, 'life1, 'async_trait>(
        &'life0 self,
        collection_href: &'life1 str,
    ) -> Pin<Box<dyn Future<Output = Result<Vec<ItemRef>, Error>> + Send + 'async_trait>>
    where
        Self: 'async_trait,
        'life0: 'async_trait,
        'life1: 'async_trait,

Rendered docs: https://mirror.whynothugo.nl/vdirsyncer/v2.0.0-beta0/vstorag...

Source: https://git.sr.ht/~whynothugo/vdirsyncer-rs/tree/v2.0.0-beta...