docs: public synchronized void destroy(NodeReferences refs) throws ItemStateException {
          if (!initialized) {
              throw new IllegalStateException("not initialized");
          }
  
          try {
              conHelper.exec(nodeReferenceDeleteSQL, getKey(refs.getTargetId()));
          } catch (Exception e) {
              if (e instanceof NoSuchItemStateException) {
                  throw (NoSuchItemStateException) e;
              }
              String msg = "failed to delete " + refs;
              log.error(msg, e);
              throw new ItemStateException(msg, e);
          }
      }