public RODRecordList getOverlapping(final GenomeLoc loc) {
if ( lastQuery != null && loc.getStart() < lastQuery.getStart() )
throw new IllegalArgumentException(String.format("BUG: query interval (%s) starts before the previous interval %s", loc, lastQuery));
readOverlappingFutureFeatures(loc);
return new RODRecordListImpl(name, subsetToOverlapping(loc, currentFeatures), loc);
}