code: public boolean checkIdle (long idleStamp)
      {
          if (_lastEvent > idleStamp) {
              return false;
          }
          if (!isClosed()) {
              log.info("Disconnecting non-communicative client",
                       "conn", this, "idle", (System.currentTimeMillis() - _lastEvent) + "ms");
          }
          return true;
      }
docs: from interface NetEventHandler