I'm assuming your language has types which don't have default values because default values for every type are a billion dollar mistake that no modern language should have.
[1] https://koka-lang.github.io/koka/doc/book.html#sec-return
Unless you are manually matching on the the Maybe, and thus observing the timeout, then that isn't the case. You'd probably also want a nondetermism effect which cannot handle unless you specifically build your timeouts to be deterministic, which I think Lean 4 does, but you can't go from partial to total with it afaik.