public async Task SendAppCardMessage(string conversationId, AppCard appCard)
        {
            WebSocketMessage msg = new WebSocketMessage
            {
                id      = Guid.NewGuid().ToString(),
                action  = "CREATE_MESSAGE",
                @params = new Params
                {
                    conversation_id = conversationId,
                    category        = "APP_CARD",
                    status          = "SENT",
                    message_id      = Guid.NewGuid().ToString(),
                    data            = Convert.ToBase64String(Encoding.UTF8.GetBytes(appCard.ToString()))
                }
            };

            await SendMessage(msg);
        }