The TLDR of their reasoning is Go’s garbage collection was causing performance problems at scale. Since Rust doesn’t have a garbage collector, it allowed the team to manage their memory use more effectively. Their results were… uplifting:

Remarkably, we had only put very basic thought into optimization as the Rust version was written. Even with just basic optimization, Rust was able to outperform the hyper hand-tuned Go version. This is a huge testament to how easy it is to write efficient programs with Rust compared to the deep dive we had to do with Go.

This is not a Go sucks switch to Rust story. It is a well-reasoned argument for using one technology over the other when it makes sense to do so.

When starting a new project or software component, we consider using Rust. Of course, we only use it where it makes sense.