@Override
  public void serialize(DataOutputStream stream) throws IOException {
    stream.writeShort(ProcedureType.ALTER_CONSUMER_GROUP_PROCEDURE.getTypeCode());
    super.serialize(stream);

    if (updatedConsumerGroupMeta != null) {
      ReadWriteIOUtils.write(true, stream);
      updatedConsumerGroupMeta.serialize(stream);
    } else {
      ReadWriteIOUtils.write(false, stream);
    }

    if (existingConsumerGroupMeta != null) {
      ReadWriteIOUtils.write(true, stream);
      existingConsumerGroupMeta.serialize(stream);
    } else {
      ReadWriteIOUtils.write(false, stream);
    }
  }
This is only used when the subscription info lock is held by another procedure.
iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/procedure/impl/subscription/consumer/AlterConsumerGroupProcedure.java