isSameDayOrAfter method
Checks if other is the same day as this or in the future.
Example usage:
final date1 = DateTime(2020, 1, 1);
final date2 = DateTime(2020, 1, 1, 12, 0, 0);
print(date1.isSameDayOrAfter(date2)); // true
Implementation
bool isSameDayOrAfter(DateTime other) => isAfter(other) || isSameDay(other);