ImpactsSource

Shallow-advance to target. This is cheaper than calling DocIdSetIterator.advance and allows further calls to .getImpacts to ignore doc IDs that are less than target in order to get more precise information about impacts. This method may not be called on targets that are less than the current DocIdSetIterator.docID. After this method has been called, DocIdSetIterator.nextDoc may not be called if the current doc ID is less than `target