visibleCalendarRange method
Implementation
DateRange visibleCalendarRange([int firstDayOfWeek = DateTime.saturday]) {
final start = monthStart.lastDateAs(firstDayOfWeek, returnIfToday: true);
final end = monthEnd.nextDateAs(firstDayOfWeek, returnIfToday: true);
return DateRange(
start: start,
end: end.addDays(-1),
);
}