Rustaceans at the border

> Should we copy the crate into the kernel tree to be independent of crates.io?

As mentioned in a comment above, there's precedent with things like zstd, which is also fully copied into the kernel tree instead of being kept as an external package. So I'd expect every crate included in the kernel, with the exception of the ones which come with the compiler (i.e. the "core" crate), to be vendored directly into the kernel tree.