A Rust `no_std` library to use userspace Linux ABI designed to have no overhead,
but still be safe when possible by leveraging Rust's type system.

The code must be carefully organized such that someone who has not read it yet
can quickly guess what a file corresponds to, or where something is implemented,
and how it works: it must be hackable without reading lots of context.

An implication is that the style must remain coherent across the code base, to
make the organization predictable.

Code duplication must be avoided, but only when the duplicated piece of code
makes sense as a whole, and has a descriptive name that fits well enough.