presto-main/src/main/java/io/prestosql/sql/planner/optimizations/PlanNodeSearcher.java/PlanNodeSearcher/findAll
class PlanNodeSearcher:    public <T extends PlanNode> List<T> findAll()
    {
        ImmutableList.Builder<T> nodes = ImmutableList.builder();
        findAllRecursive(node, nodes);
        return nodes.build();
    }