sendFileMessage method Null safety
Send file messages
messageUuidmessage identifier, used to track the progress of attachment upload. You can generatre identifiers usingUUID.randomUUID().filePathfile pathuserUuidslist of user Ids. If empty, all members will receive messages.
Implementation
Future<VoidResult> sendFileMessage(
  String messageUuid,
  String filePath,
  List<String>? userUuids,
);