presto-main/src/main/java/io/prestosql/util/GraphvizPrinter.java/NodePrinter/visitUnnest
class NodePrinter:        @Override
        public Void visitUnnest(UnnestNode node, Void context)
        {
            StringBuilder label = new StringBuilder();
            if (node.getFilter().isPresent()) {
                label.append(node.getJoinType().getJoinLabel())
                        .append(" Unnest");
            }
            else if (!node.getReplicateSymbols().isEmpty()) {
                label.append("CrossJoin Unnest");
            }
            else {
                label.append("Unnest");
            }
            label.append(format(" [%s", node.getUnnestSymbols().keySet()))
                    .append(node.getOrdinalitySymbol().isPresent() ? " (ordinality)]" : "]");

            String details = node.getFilter().isPresent() ? " filter " + node.getFilter().get().toString() : "";

            printNode(node, label.toString(), details, NODE_COLORS.get(NodeType.UNNEST));
            return node.getSource().accept(this, context);
        }