A Guided Tour of Streams in Rust

Streams in Rust can be understood as asynchronous iterations, offering a way to handle sequences in an async context, similar to how iterators work in synchronous scenarios. In Rust, an iterator requires an associated type and a next() method that returns an Option, which helps signal when there are no more elements to retrieve, thus providing a safer API by merging the functionality of hasNext() and next() found in Java. Streams, defined by the Stream trait, are asynchronous iterators that utilize Rust's async and Future capabilities, with the poll function bridging the async and sync worlds by returning a Poll, which indicates the readiness of a value. The article further explores the creation and manipulation of streams using various methods such as Stream::iter and Stream::unfold, and highlights the use of the async-stream crate, which simplifies stream creation through macros like stream! and try_stream!. Additionally, it discusses different traits related to streams, such as FusedStream and TryStream, which cater to specific needs like handling circular buffers or Result items. The article concludes with an introduction to consuming streams using combinators and the importance of pinning streams before iteration, hinting at future discussions on using streams with Websockets.