code: public void addSession(AbstractIoSession session) {
          sessions.add(session);
          CloseFuture closeFuture = session.getCloseFuture();
          
          // isn't service reponsability to remove the session nicely ?
          closeFuture.addListener(sessionCloseListener);
      }
docs: Add the session for being checked for idle.
  @param session the session to check