상속: BaseMessage
        public Task SendToServerAsync(object payload)
        {
            var message = new Model.PayloadMessage
            {
                Payload = SerializePayload(payload)
            };

            return SendToServerAsync(message);
        }
        public Task SendToClientAsync(string hostId, object payload)
        {
            var message = new Model.PayloadMessage
            {
                Payload = SerializePayload(payload)
            };

            return SendToClientAsync(hostId, message);
        }