Function std::future::get_task_waker

pub fn get_task_waker<F, R>(f: F) -> R where
    F: FnOnce(&Waker) -> R, 

🔬 This is a nightly-only experimental API. (gen_future #50547)

Retrieves the thread-local task waker used by async/await futures.

This function acquires exclusive access to the task waker.

Panics if no waker has been set or if the waker has already been retrieved by a surrounding call to get_task_waker.