Crate async_stream

asynk-strim

Like async-stream but without macros. Like async-fn-stream but a little more efficient.

Features:

• macroless API
• one dependency (besides futures-core which I don’t count since it provides the Stream definition)
• no_std-compatible, zero allocations

⚠ Important

This crate adds a wrapper around the wakers that contains data and pointers needed to yield items. Crates like embassy use a similar approach and will therefore clash with us.

If you run into this issue (which will manifest as a runtime panic), you can use the unwrap_waker function. This function will wrap a future and remove the waker wrapper.

While you can’t use the yielder inside the unwrapped future, stuff like embassy should work again.

Example

use futures_lite::stream;
use std::pin::pin;

let stream = pin!(asynk_strim::stream_fn(|mut yielder| async move {
    yielder.yield_item("hello world!").await;
    yielder.yield_item("pretty neato, ain't it?").await;
}));

let mut stream = stream::block_on(stream);
assert_eq!(stream.next(), Some("hello world!"));
assert_eq!(stream.next(), Some("pretty neato, ain't it?"));
assert_eq!(stream.next(), None);

Comparisons

async-stream

In comparison to async-stream we offer the following advantages:

• no macros
• slightly faster performance
• no_std support

async-fn-stream

In comparison to async-stream we offer the following advantages:

• no allocations
• slightly faster performance
• no_std support

Acknowledgements

This crate combines approaches from the following crates:

• async-stream
• async-fn-stream
• The PR by Sabrina Jewson adding a function-based API to async-stream
• The experimental PR by Hyeonu Park using the waker-based approach

License

Licensed under tither the MIT or Apache 2.0 license (at your choosing)

Structs

TryYielder

Handle to allow you to yield something from the stream

Yielder

Handle to allow you to yield something from the stream

Functions

stream_fn

Create a new stream

strim_fn

Jokey alias for stream_fn

try_stream_fn

Create a new try stream

try_strim_fn

Jokey alias for try_stream_fn

unwrap_waker

Unwrap the waker