isSameWeek method
Checks if two dates fall within the same week.
Implementation
bool isSameWeek(DateTime b) {
final a = DateTime.utc(year, month, day);
b = DateTime.utc(b.year, b.month, b.day);
final diff = a.toUtc().difference(b.toUtc()).inDays;
if (diff.abs() >= 7) return false;
final min = a.isBefore(b) ? a : b;
final max = a.isBefore(b) ? b : a;
return max.weekday % 7 - min.weekday % 7 >= 0;
}