None = PostQueuedCompletionStatus(handle, numberOfbytes , completionKey , overlapped )
lets you post an I/O completion packet to an I/O completion port. The I/O completion packet will satisfy an outstanding call to the GetQueuedCompletionStatus function.
CommentsNote that if you post overlapped objects, but your post is closed before all pending requests are processed, the overlapped objects (including its 'handle' and 'object' members) will leak. See MS KB article Q192800 for a summary of this.