public FirebasePushResult SendNotification(FirebaseMessage message, string to = null, string[] topics = null, object data = null)
        {
            var req = new FirebaseRequest
            {
                notification = message,
                data         = data,
                to           = to
            };

            if (topics != null)
            {
                List <string> conds = new List <string>();
                foreach (var c in topics)
                {
                    conds.Add("'" + c + "' in topics");
                }
                req.condition = string.Join("||", conds);
            }

            FirebasePushResult res = new FirebasePushResult();

            try
            {
                res = PostAs <FirebasePushResult>("send", req);
            }
            catch (Exception ex)
            {
                res.success = 0;
                res.failure = 1;
                res.SetException(ex);
            }
            return(res);
        }
        public FirebasePushResult SendNotification(FirebaseRequest data)
        {
            FirebasePushResult res = new FirebasePushResult();

            try
            {
                res = PostAs <FirebasePushResult>("send", data);
            }
            catch (Exception ex)
            {
                res.SetException(ex);
            }
            return(res);
        }