code: public int[] getPartialValues(ReadablePartial fieldSource, Object object, Chronology chrono) {
          long instant = getInstantMillis(object, chrono);
          return chrono.get(fieldSource, instant);
      }
docs: Extracts the values of the partial from an object of this converter's type.
  The chrono parameter is a hint to the converter, should it require a
  chronology to aid in conversion.
  <p>
  This implementation calls {@link #getInstantMillis(Object, Chronology)}.
  
  @param fieldSource  a partial that provides access to the fields.
  This partial may be incomplete and only getFieldType(int) should be used
  @param object  the object to convert
  @param chrono  the chronology to use, which is the non-null result of getChronology()
  @return the array of field values that match the fieldSource, must be non-null valid
  @throws ClassCastException if the object is invalid