Sorry, I don't find that convincing but rather construed. This still seems like "constructor" type code, so the final object is not ready and locking should not happen before all the protected fields are constructed.

There may be other situations where you have an object in a specific state that makes it effectively owned by a thread, which might make it possible to forgo locking it. These are all very ad-hoc situations, most of them would surely be very hard to model using the borrow checker, and avoiding a lock would most likely not be worth the hassle anyway.

Not sure how this can help me reduce complexity or improve performance of my software.