We once-again have a Rust toolchain bootstrap as part of our Darwin Guix builds. While not necessarily bad, this consumes a fairly significant amount of additional time / resources when bootstrapping, and may make it harder to bootstrap on some platforms. It's probably inevitable that we'll have to bootstrap a Rust toolchain in future (for all HOSTS) whenever Rust becomes a dependency of a more core utility or library, but for now, if it's easy to do, we could prune it out.

The chain to Rust is:

python-signapple -> python-requests -> python-urllib3 -> python-cryptography -> python-cryptography-rust.

The easiest solution here might just be to change signapple to not use python-requests for it's timestamping POST:

https://github.com/achow101/signapple/blob/48ba6fe3f92ca9e035c5056126524aaea4bfacb0/signapple/sign.py#L267

and use the Python standard library: https://docs.python.org/3/library/urllib.request.html#module-urllib.request instead.