presto-main/src/main/java/io/prestosql/sql/planner/optimizations/joins/JoinGraph.java/JoinGraph/visitProject
class JoinGraph:        @Override
        public JoinGraph visitProject(ProjectNode node, Context context)
        {
            Optional<PlanNode> rewrittenNode = pushProjectionThroughJoin(metadata, node, lookup, planNodeIdAllocator);
            if (rewrittenNode.isPresent()) {
                return rewrittenNode.get().accept(this, context);
            }

            return visitPlan(node, context);
        }