Rust Async's Main Libraries

Rust, unlike Go, does not have a built-in asynchronous runtime like goroutines. Instead, asynchronous programming in Rust relies on external libraries, offering developers more flexibility but requiring some setup.

1. tokio: The most popular async runtime in Rust, widely used for high-performance network applications. It provides a multithreaded scheduler, async I/O, timers, and more. Its ecosystem includes utilities like tokio::fs and tokio::net, making it ideal for web services.

2. async-std: Modeled after Rust's standard library, this runtime offers familiar abstractions like File, TcpStream, and Mutex in an async context. It's known for ease of use and compatibility with existing code.

3. smol: A lightweight, minimal runtime with a focus on simplicity. Smol is perfect for smaller projects where performance isn't the primary concern.

These libraries allow developers to write non-blocking code in Rust, offering various levels of abstraction and performance depending on project needs.