I like the bit about CPS, but wish it show how do the last part without having the async machinery in the host language. What I have a hard time to get is how

I like the bit about CPS, but wish it show how do the last part without having the async machinery in the host language. What I have a hard time to get is how implement fully delimited continuations. All the examples I know reuse the machinery of the host so is hard to translate (in my case, to Rust)