use io;
use crateSelector;
use crateToken;
/// Waker backed by kqueue user space notifications (`EVFILT_USER`).
///
/// The implementation is fairly simple, first the kqueue must be setup to
/// receive waker events this done by calling `Selector.setup_waker`. Next
/// we need access to kqueue, thus we need to duplicate the file descriptor.
/// Now waking is as simple as adding an event to the kqueue.
pub