Concurrency

How `Send` and `Sync` let the compiler catch data races at compile time, and the trade-off between shared-state concurrency (`Mutex`/`Arc`) and message-passing concurrency (channels).

Threads, joining, and the concurrency model.

`std::sync::mpsc`, `crossbeam`, and message passing.

Shared mutable state with locking.

Combining `Arc` with locks across threads.

Parallel iterators and work-stealing.

Sharing by communicating, minimizing locks.