pub unsafe fn unpark_all(key: usize, unpark_token: UnparkToken) -> usize
Unparks all threads in the queue associated with the given key.
UnparkToken is passed to all unparked threads.
This function returns the number of threads that were unparked.
You should only call this function with an address that you control, since you could otherwise interfere with the operation of other synchronization primitives.