Is there a way to poll several futures simultaniously in rust async

Question

I'm trying to execute several sqlx queries in parallel given by a iterator. This is probably the closest I've got so far.

let mut futures = HahshMap::new() // placeholder, filled HashMap in reality
    .iter()
    .map(async move |(_, item)| -> Result<(), sqlx::Error> {
        let result = sqlx::query_file_as!(
            // omitted
        )
            .fetch_one(&pool)
            .await?;
        channel.send(Enum::Event(result)).ignore();
        Ok(())
    })
    .clollect();
futures::future::join_all(futures);

All queries and sends are independent from each other, so if one of them fails, the others should still get processed. Futthermore the current async closure is not possible like this.

Answer 1

Rust doesn't yet have async closures. You instead need to have the closure return an async block:

move |(_, item)| async move { ... }

Additionally, make sure you .await the future returned by join_all in order to ensure the individual tasks are actually polled.