@Override
  public void beforeStart(UDFParameters parameters, UDTFConfigurations configurations)
      throws Exception {
    dataType = parameters.getDataType(0);
    configurations.setAccessStrategy(new RowByRowAccessStrategy()).setOutputDataType(dataType);
  }
This function is used to calculate the spread of time series, that is, the maximum value minus
the minimum value.
library-udf/src/main/java/org/apache/iotdb/library/dprofile/UDAFSpread.java