Uninitialized Memory: Unsafe Rust is Too Hard
Rust is in many ways not just a modern systems language, but also quite a pragmatic one. It promises safety and provides an entire framework that makes creating safe abstractions possible with minimal to zero runtime overhead. A well known pragmatic solution in the language is an explicit way to opt out of safety by using unsafe. In unsafe blocks anything goes.
Source: Uninitialized Memory: Unsafe Rust is Too Hard, an article by Armin Ronacher.