docs: public void destroy() {
          PortletFilter delegateToUse = null;
          delegateReadLock.lock();
          try {
              delegateToUse = this.delegate;
          }
          finally {
              delegateReadLock.unlock();
          }
  
          if (delegateToUse != null) {
              destroyDelegate(delegateToUse);
          }
      }