code: public static ChronoFunction<Moment, PlainTimestamp> onAverage(ZonalOffset offset) {
  
          return context -> onAverage(context, offset);
  
      }
docs: /*[deutsch]
  <p>Ermittelt die mittlere Ortszeit zur angegebenen lokalen Zeitzonendifferenz. </p>
  
  @param   offset      the time zone offset which might depend on the geographical longitude
  @return  function for getting the mean solar time
  @see     ZonalOffset#atLongitude(OffsetSign, int, int, double)