presto-main/src/main/java/io/prestosql/sql/planner/planprinter/PlanPrinter.java/PlanPrinter/visitProject
class PlanPrinter:        @Override
        public Void visitProject(ProjectNode node, Void context)
        {
            if (node.getSource() instanceof FilterNode) {
                return visitScanFilterAndProjectInfo(node, Optional.of((FilterNode) node.getSource()), Optional.of(node), context);
            }

            return visitScanFilterAndProjectInfo(node, Optional.empty(), Optional.of(node), context);
        }