private SimplerDirectSsdWriter(ImmutableList <Pin> segmentPins, ImmutableList <Pin> digitPins,
                                GpioHandler handler, Func <int, byte> values, int?currentDigit = null)
 {
     this.segmentPins  = segmentPins;
     this.digitPins    = digitPins;
     this.handler      = handler;
     this.values       = values;
     this.currentDigit = currentDigit ?? digitPins.Count - 1;
 }
        public SimplerDirectSsdWriter(ImmutableList <Pin> segmentPins, ImmutableList <Pin> digitPins,
                                      GpioHandler handler)
        {
            this.segmentPins  = segmentPins;
            this.digitPins    = digitPins;
            this.handler      = handler;
            this.values       = (arg) => 0;
            this.currentDigit = digitPins.Count - 1;

            Debug.Assert(this.segmentPins.Count == 8);
        }