Futures-based `with_document`

[LilithSilver]

I'm constantly using the following construction:

let something = tokio::task::spawn_blocking(move || {
    handle.with_document(|d| {
        // ... do some stuff
    })
})
.await.unwrap();

Would it be possible to have a version that is futures-compatible, so I could call it like this?

let something = handle.with_document(|d| {
    // ... do some stuff
}).await;

If that's desired, I'd recommend the old one be called blocking_with_document to really emphasize that it blocks, and the new renamed to with_document to match rust's naming (though that would be an API change).