FTopicMessage constructor
      
      FTopicMessage({ 
    
    
- required String topic,
- Map<String, String> ? data,
- FNotification? notification,
- FAndroidConfig? android,
- FWebpushConfig? webpush,
- FApnsConfig? apns,
- FFcmOptions? fcmOptions,
Implementation
FTopicMessage({
  required this.topic,
  super.data,
  super.notification,
  super.android,
  super.webpush,
  super.apns,
  super.fcmOptions,
}) : super._();