toMap method Null safety
Implementation
Map<String, dynamic> toMap() => <String, dynamic>{
"messageId": messageId,
if (type != null)
"type": SystemMessageTypeConverter(type: type).toValue(),
"fromAccount": fromAccount,
"targetId": targetId,
"time": time,
if (status != null)
"status": SystemMessageStatusConverter(status: status).toValue(),
"content": content,
"attach": attach,
"unread": unread,
"customInfo": customInfo
};