what is futures-rs fr?

futures-rs is an official Rust library that provides building blocks for writing asynchronous code. Asynchronous programming lets a program do other work while waiting for slow operations, like network requests or file reads, rather than sitting idle. This library is part of the Rust programming language project itself and defines the core abstractions that make that pattern possible in Rust. The library includes key pieces like Stream, which is a sequence of values produced over time, and utility macros like join! and select! that let you wait on multiple asynchronous operations at once in a readable way. It also provides a collection of combinator methods that let you chain and transform asynchronous operations without deeply nested callbacks. One of the stated goals is zero cost: the abstractions in the library are designed so that using them does not add runtime overhead compared to writing the equivalent low-level code by hand. The library can also run in environments without an operating system, such as embedded hardware, by disabling its standard library features. To use it, you add a single line to your Rust project's dependency file and specify version 0.3. The library requires Rust version 1.71 or newer. The README is short and points to the documentation at docs.rs/futures and the project website for more detail.