docs: public static void setToDefault ()
    {
      s_aRWLock.writeLocked ( () -> {
        s_nMaxMailQueueLen = DEFAULT_MAX_QUEUE_LENGTH;
        s_nMaxMailSendCount = DEFAULT_MAX_SEND_COUNT;
        s_bUseSSL = DEFAULT_USE_SSL;
        s_bUseSTARTTLS = DEFAULT_USE_STARTTLS;
        s_nConnectionTimeoutMilliSecs = DEFAULT_CONNECT_TIMEOUT_MILLISECS;
        s_nTimeoutMilliSecs = DEFAULT_TIMEOUT_MILLISECS;
        s_bDebugSMTP = GlobalDebug.isDebugMode ();
        s_aConnectionListeners.clear ();
        s_aEmailDataTransportListeners.clear ();
      });
    }