docs: protected boolean markOffline(Computer c, OfflineCause oc) {
          if(isIgnored() || c.isTemporarilyOffline()) return false; // noop
  
          c.setTemporarilyOffline(true, oc);
  
          // notify the admin
          MonitorMarkedNodeOffline no = AdministrativeMonitor.all().get(MonitorMarkedNodeOffline.class);
          if(no!=null)
              no.active = true;
          return true;
      }