Handle wrapping the eventfd descriptor on success, or an
invalid Handle if eventfd creation fails.
Create an eventfd handle for wakeup notifications.
Creates a non-blocking eventfd with close-on-exec flag set. The eventfd counter starts at zero and can be incremented by writing and read/reset by reading.
Handle wrapping the eventfd descriptor on success, or an
invalid Handle if eventfd creation fails.
writeWakeup, readWakeup