Header constructor Null safety

Header(
  1. {AppSequence? appSequence,
  2. required int messageID,
  3. required String relatesTo,
  4. required String to,
  5. required String action}
)

Implementation

Header(
    {this.appSequence,
    required this.messageID,
    required this.relatesTo,
    required this.to,
    required this.action});