code: public void close () {
      if (lc_dev_proxy != null) {
        try {
          DeviceData dd = new DeviceData();
          dd.insert(dev_name);
          lc_dev_proxy.command_inout_asynch("UnRegister", dd, true);
        }
        catch (DevFailed dv) {
          //Ignore: some old LogViewer may not support the Unregister cmd
        }
      }
      lc_dev_proxy = null; 
      dev_name = null;
    }
docs: Release any resources allocated within the appender.