VDKQueue is an Objective-C wrapper for the kqueue(2) file-activity-monitoring facility in OS X.
VDKQueue is an open-source wrapper, written in Objective-C, for OS X's kevent(2) and kqueue(2) functions, used for monitoring activity on files and directories.
It was developed by Bryan, a.k.a. bdkjones, as a more modern successor to Uli Kusterer's UKKQueue. He announced it here on Stack Overflow in an answer to a question about UKKQueue.