[coroutine.handle.resumption]

Resuming a coroutine via resume, operator(), or destroy on an execution agent other than the one on which it was suspended has implementation-defined behavior unless each execution agent either is an instance of std::thread or std::jthread, or is the thread that executes main.

[Note 1:

A coroutine that is resumed on a different execution agent should avoid relying on consistent thread identity throughout, such as holding a mutex object across a suspend point.

— end note]

[Note 2:

A concurrent resumption of the coroutine can result in a data race.

— end note]

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void operator()() const;
void resume() const;

Effects: Resumes the execution of the coroutine.

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void destroy() const;

Effects: Destroys the coroutine ([dcl.fct.def.coroutine]).