public PlanNode defaultRewrite(PlanNode node) {
      return defaultRewrite(node, null);
    }
Invoke the rewrite logic recursively on children of the given node and swap it out with an
identical copy with the rewritten children
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/planner/SimplePlanRewriter.java