Unfortunately, the Sync module is the least straight-forward one in the entire library at the moment (in my opinion). I have a branch lying around on my machine that switches everything to TypeScript, so that it’s easier to make sense of all the values being passed around, which I did so I could start refactoring it in the first place.
I didn’t get to the types yet, because it was a bit of an effort to convert everything to modern classes first. Just pushed the branch, in case anyone is interested in helping with this.