public virtual async Task invoke()
            {
                if (_value == null)
                {
                    YSensor  sensor = (YSensor)_fun;
                    YMeasure mesure = await sensor._decodeTimedReport(_timestamp, _report);

                    await sensor._invokeTimedReportCallback(mesure);
                }
                else
                {
                    // new value
                    await _fun._invokeValueCallback(_value);
                }
            }