A Mental Model for C++ Coroutine

C++ coroutine is not a library that is ready to go (e.g. std::vector). It is not even a trait (think of Rust’s Future trait) that library writers or users can implement (or the compiler generates for you in the case of Rust). C++ coroutine is a specification that defines a set of customization points that library writers implement in order to get a functional coroutine.