Resource leakage in RegNotifyChangeKeyValue

Question

The MSDN mentions:

Each time a process calls RegNotifyChangeKeyValue with the same set of parameters, it establishes another wait operation, creating a resource leak. Therefore, check that you are not calling RegNotifyChangeKeyValue with the same parameters until the previous wait operation has completed.

http://msdn.microsoft.com/en-us/library/ms724892(VS.85).aspx

I would like to know what kind of resource leakage is being described above? How to detect that leakage using any tool?