private static void IdleServicePointTimeoutCallback(TimerThread.Timer timer, int timeNoticed, object context)
        {
            ServicePoint servicePoint = (ServicePoint)context;

            if (Logging.On)
            {
                Logging.PrintInfo(Logging.Web, SR.GetString(SR.net_log_closed_idle,
                                                            "ServicePoint", servicePoint.GetHashCode()));
            }

            lock (s_ServicePointTable)
            {
                s_ServicePointTable.Remove(servicePoint.LookupString);
            }

            servicePoint.ReleaseAllConnectionGroups();
        }