3.4.7.9 Volume Modification
When the server detects that a volume was modified, for each callback object that is registered in the list of callback objects, the server MUST call the callback object's IVdsAdviseSink::OnNotify (section 3.3.4.3.1) method by using a VDS_NOTIFICATION (section 2.2.1.3.9) structure that has the following attributes:
objectType member is VDS_NTT_VOLUME.
Volume member is a VDS_VOLUME_NOTIFICATION (section 2.2.1.3.4) with the following attributes:
ulEvent is VDS_NF_VOLUME_MODIFY.
volumeId is the VDS_OBJECT_ID (section 2.2.1.1.3) of the volume object.
plexId SHOULD be GUID_NULL, but it is not relevant when ulEvent is VDS_NF_VOLUME_MODIFY.
ulPercentCompleted needs to be from 0 to 100 and is implementation-specific, but it is not relevant when ulEvent is VDS_NF_VOLUME_MODIFY.