Function async_fn_stream::try_fn_stream

pub fn try_fn_stream<T, E, Fut: Future<Output = Result<(), E>>>(
    func: impl FnOnce(StreamEmitter<T>) -> Fut
) -> TryFnStream<T, E, Fut>

Create a new fallible stream which is implemented by func.

Caller should pass an async function which will return successive stream elements via StreamEmitter::emit or returns errors as Result::Err.

Example

use async_fn_stream::try_fn_stream;
use futures::Stream;

fn build_stream() -> impl Stream<Item = Result<i32, anyhow::Error>> {
    try_fn_stream(|emitter| async move {
        for i in 0..3 {
            // yield elements from stream via `emitter`
            emitter.emit(i).await;
        }

        // return errors as `Result::Err`
        Err(anyhow::anyhow!("An error happened"))
    })
}