@Override
    public Object setValue(Object row, ColumnVector column, int columnRow)
        throws HiveException {

      // NULLs are handled by each individual base writer setter
      // We could handle NULLs centrally here but that would result in spurious allocs

      Object fieldValue = this.settableObjInspector.getStructFieldData(row, fieldRef);
      fieldValue = baseWriter.setValue(fieldValue, column, columnRow);
      return this.settableObjInspector.setStructFieldData(row, fieldRef, fieldValue);
    }
VectorExpressionWriterSetter helper for vector expression writers that use
settable ObjectInspector fields to assign the values.
This is used by the OrcStruct serialization (eg. CREATE TABLE ... AS ...)
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/VectorExpressionWriterFactory.java