Crossbeam is a library that provides various concurrency primitives, such as a queue type that allows stealing of work. Rayon is a library for running code in

Crossbeam is a library that provides various concurrency primitives, such as a queue type that allows stealing of work. Rayon is a library for running code in parallel. Typically you'll give it a (parallel) iterator of sorts, and it will distribute the work across a pool of threads. Tokio is a library for async IO operations.