presto-main/src/main/java/io/prestosql/util/GraphvizPrinter.java/GraphvizPrinter/visitTopNRowNumber
class GraphvizPrinter:        @Override
        public Void visitTopNRowNumber(TopNRowNumberNode node, Void context)
        {
            printNode(node,
                    "TopNRowNumber",
                    format("partition by = %s|order by = %s|n = %s",
                            Joiner.on(", ").join(node.getPartitionBy()),
                            Joiner.on(", ").join(node.getOrderingScheme().getOrderBy()), node.getMaxRowCountPerPartition()),
                    NODE_COLORS.get(NodeType.WINDOW));
            return node.getSource().accept(this, context);
        }