This method should return a list of the records that have been deleted from the complex table since the client's last update time, which can be retrieved via getClientLastDataUpdateTime()).
It returns these records in the form of a Iterator object that iterates over a list of objects that identify the deleted records via their unique keys. Subclasses should override this method to return the desired data. Note that the objects returned do not need to be fully populated, they only need to contain their unique identifiers (which are configured in the Agentry application).
The actual behavior of this method is dependent on the result of the willRebuildTable() method. If that method returns false, then this method should return a list of deleted records. If that method returns true, then this method should return an empty iterator. The default behavior of this method is to return an empty iterator, so if your willRebuildTable() implementation will always return true, then you don't need to override this method.
Note that in some versions of Agentry, this method may not be called at all if willRebuildTable() returns true, since there should be no deleted objects in that case.