floatToTime24 method
Implementation
String floatToTime24(double time) {
if (time.isNaN) return InvalidTime;
time = fixhour(time + 0.5 / 60); // add 0.5 minutes to round
final int minutes = ((time - time.floor()) * 60).floor();
return '${twoDigitsFormat(time.floor())}:${twoDigitsFormat(minutes)}';
}