Another cool tool that’s being developed for rust is verus. It’s not the same as Kani and is more of a fork of the rust compiler but it lets you do some cool verification proofs combined with the z3 SMT solver. It’s really a cool system for verified programs.

I had a look, and it seems cool. But it doesn't seem to do the thing I love about Kani: work with only very partial annotations, only proving the annotations and being a very light lift on code not relevant for the annotations.