Tokio (async)

Tokio is the industry-standard runtime for writing reliable, asynchronous, and slim network applications with the Rust programming language.

Tokio provides the essential building blocks for high-concurrency Rust services: a multi-threaded scheduler based on work-stealing, a non-blocking I/O driver (mio), and a high-performance timer library. It powers mission-critical infrastructure at companies like Discord and AWS by handling thousands of simultaneous connections with minimal overhead. Developers use its specialized primitives (select!, join!, and mpsc channels) to manage complex asynchronous workflows without the memory safety risks common in C++. By abstracting the underlying epoll or kqueue system calls, Tokio allows a single process to scale across all available CPU cores while maintaining sub-millisecond tail latencies.

https://tokio.rs