Rust ensures that while one thread is accessing a datastructure that no other thread will modify it. It does this by only allowing you to have either one mutabl

Rust ensures that while one thread is accessing a datastructure that no other thread will modify it. It does this by only allowing you to have either one mutable or multiple readonly references to a datastructure. Code marked unsafe could violate this, which is why it should be rare and well reviewed.