You might be waiting a while, there are zero Rust repositories in their open source repertoire: https://github.com/uber

I would love to see that too, but I think that's likely never happened. Because Rust is kinda hard and takes quite amount of time and money to train new people, add more stacks on maintaining projects, and important thing is that I don't see why they have to use Rust. Go is good enough and they can work around with Go's disavantages.