private void Subscribe(SubscriptionMessage.Subscription message)
        {
            var context = RequestContext.Current;

            context.Server.SubscriptionManager.Add(new ServerSubscription
            {
                ConnectionId   = context.ConnectionId,
                SubscriptionId = message.SubscriptionId,
                EventName      = message.EventName,
                EventFilter    = message.EventFilter,
            });
        }
        private void Unsubscribe(SubscriptionMessage.Subscription message)
        {
            var context = RequestContext.Current;

            context.Server.SubscriptionManager.Remove(message.EventName, context.ConnectionId, message.SubscriptionId);
        }