Favorite Rust Feature

Rust is a powerful, modern language with many important features like memory safety, borrow checking, and zero-cost abstractions. My favorite Rust feature is something that is deeply involved in all of those things: the Arc struct.

With Arc, we have an atomic reference count type that we can wrap any other type inside. When we use an Arc, we can copy just the size of the Arc (8 bytes) instead of the actual type. And data inside an arc is guaranteed to be safe to access on many threads.

There are some limitations:

Arc is best used when a program has multiple threads. When beginning to learn Rust, I remember changing a type to be encapsulated in an Arc, and then realizing a significant performance improvement when the amount of data copied to new threads was vastly decreased.