This is a tracking issue for the RFC "2996" (rust-lang/rfcs#2996).
The feature gate for the issue is #![feature(async_iterator)].

About tracking issues

Tracking issues are used to record the overall progress of implementation.
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.

Steps

• Implement the RFC (cc @rust-lang/XXX -- can anyone write up mentoring
  instructions?)
• Adjust documentation (see instructions on rustc-dev-guide)
• Stabilization PR (see instructions on rustc-dev-guide)

Unresolved Questions

• Clarify the panic behavior of Stream and Iterator Add core::stream::Stream #79023 (comment)
  • Add a panic section to Iterator, clarifying panic behavior. The panic behavior between Stream and Iterator should be consistent.
• Restore Stream::next. This was removed from the RFC because it prevents dynamic dispatch, and subsequently removed from the implementation. This should be resolved before stabilizing.
  • Investigate whether we can move the trait from fn poll_next to async fn next once we can use async in traits.
• Investigate as part of keyword-generics whether we can merge Iterator and AsyncIterator into a single trait which is generic over "asyncness".
• Should we name this API AsyncIterator instead? Tracking Issue for #![feature(async_iterator)] #79024 (comment)

Implementation history

• PR introducing core::stream::{Stream, Next}
• Rename from Stream to AsyncIterator