public static void serialize(Expression expression, DataOutputStream stream) throws IOException {
    ReadWriteIOUtils.write(expression.getExpressionType().getExpressionTypeInShortEnum(), stream);

    expression.serialize(stream);

    ReadWriteIOUtils.write(expression.inputColumnIndex != null, stream);
    if (expression.inputColumnIndex != null) {
      ReadWriteIOUtils.write(expression.inputColumnIndex, stream);
    }
  }
Sub-classes must not override this method.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/expression/Expression.java