[$] Canceling asynchronous Rust

Asynchronous Rust code has what Rain Paharia calls a 'universal cancellation
protocol', meaning that any asynchronous code can be interrupted in the same
way. They claim
that this is both a useful feature when used deliberately, and a source of
errors when done by accident. They presented
about this problem at

RustConf 2025, offering a handful of techniques to avoid introducing bugs into
asynchronous Rust code.