isDaylightSaving property

Indicates whether this date-time is in daylight saving time.

Example:

final summer = ZonedDateTime.of(
  LocalDateTime.of(2023, 7, 15, 12, 0),
  ZoneId.of('America/New_York')
);
final winter = ZonedDateTime.of(
  LocalDateTime.of(2023, 1, 15, 12, 0),
  ZoneId.of('America/New_York')
);

print('Summer DST: ${summer.isDaylightSaving}'); // true
print('Winter DST: ${winter.isDaylightSaving}'); // false