docs: static byte[] writePlanBytes(PlanFragment fragment, AbstractPlanNode planGraph) {
          // get the plan bytes
          PlanNodeList node_list = new PlanNodeList(planGraph, false);
          String json = node_list.toJSONString();
          // Place serialized version of PlanNodeTree into a PlanFragment
          byte[] jsonBytes = json.getBytes(Charsets.UTF_8);
          String bin64String = CompressionService.compressAndBase64Encode(jsonBytes);
          fragment.setPlannodetree(bin64String);
          return jsonBytes;
      }