public Map<String, Tuple<Boolean, Map<String, Long>>> getCountersByDocId() {
        if (_countersByDocId == null) {
            _countersByDocId = new TreeMap<>(String::compareToIgnoreCase);
        }
        return _countersByDocId;
    }
public Map < String , Tuple < Boolean , Map < String , Long > > > getCountersByDocId ( ) { if ( _countersByDocId == null ) { _countersByDocId = new TreeMap < > ( String :: compareToIgnoreCase ) ; } return _countersByDocId ; }
@return map which holds the data required to manage Counters tracking for RavenDB's Unit of Work