sn property

@override int get sn

Serial number (unique message identifier).

This integer serves as a unique ID for the message, used for deduplication, tracking, and acknowledgment of message delivery.

Implementation

@override
int get sn {
  _sn ??= getInt('sn', 0);
  assert(_sn! > 0, 'serial number error: ${super.toMap()}');
  return _sn ?? 0;
}