presto-main/src/main/java/io/prestosql/sql/planner/optimizations/WindowFilterPushDown.java/WindowFilterPushDown/convertToTopNRowNumber
class WindowFilterPushDown:        private TopNRowNumberNode convertToTopNRowNumber(WindowNode windowNode, int limit)
        {
            return new TopNRowNumberNode(idAllocator.getNextId(),
                    windowNode.getSource(),
                    windowNode.getSpecification(),
                    getOnlyElement(windowNode.getWindowFunctions().keySet()),
                    limit,
                    false,
                    Optional.empty());
        }