docs: private void closeSession(){
          if(LOGGER.isDebugEnabled()){
              LOGGER.debug("Close the session, sessionId=" + session.id + ", timeOut=" + session.timeOut);
          }
          if(! closing && getStatus().isConnected()){
              closing = true;
              if(getStatus().isAlive()){
                  setStatus(ConnectionStatus.NOT_CONNECTED);
              }
              cleanupSession();
              closing = false;
          }
      }