tempsByHct property
A Map with keys of HCTs in hctsByTemp, values of raw temperature.
Implementation
Map<Hct, double> get tempsByHct {
  if (_tempsByHct.isNotEmpty) {
    return _tempsByHct;
  }
  final allHcts = List<Hct>.from(hctsByHue)..add(input);
  final temperaturesByHct = {for (var e in allHcts) e: rawTemperature(e)};
  _tempsByHct = temperaturesByHct;
  return _tempsByHct;
}