How to monitor local documents directory NSMetaDataQuery

I've been looking for an answer to this question and, according to the documentation (Searching iCloud and the Desktop), it's not possible:

Unlike the desktop, the iOS application’s sandbox is not searchable using the metadata classes. In order to search your application’s sandbox, you will need to traverse the files within the sandbox file system recursively using the NSFileManager class.

On Mac OS X three additional scopes are defined: NSMetadataQueryUserHomeScope, NSMetadataQueryLocalComputerScope and NSMetadataQueryNetworkScope which can be used to achieve this.