Index of the first day of week, where 0 points to Sunday, and 6 points to Saturday.
This getter is compatible with narrowWeekdays. For example:
var localizations = MaterialLocalizations.of(context); // The name of the first day of week for the current locale. var firstDayOfWeek = localizations.narrowWeekdays[localizations.firstDayOfWeekIndex];
@override int get firstDayOfWeekIndex => 0;