Thanks! Operational transformation is the same technology that powers Google Docs. It's been studied in academia for real-time collaboration since the 1990s and has eventual consistency guarantees. See the Wikipedia article: https://en.wikipedia.org/wiki/Operational_transformation

The Rust operational-transform library was not written by me, but it's listed on crates.io by spebern, and it's worked wonderfully so far. It seems to be a very close port of ot.js (https://github.com/Operational-Transformation/ot.js). The text transformation algorithm isn't very complicated (<700 SLOC including tests), but there's probably room for optimization!