@Override
  public void beforeStart(UDFParameters parameters, UDTFConfigurations configurations)
      throws Exception {
    dataType = parameters.getDataType(0);
    configurations.setAccessStrategy(new RowByRowAccessStrategy()).setOutputDataType(dataType);
  }
Return a series that the consecutive identical values in input series are removed (keeping only
the first one).
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/udf/builtin/UDTFChangePoints.java