code: public void addItem (@Nonnull final ReIndexWorkItem aItem) throws IllegalStateException
    {
      ValueEnforcer.notNull (aItem, "Item");
      m_aRWLock.writeLocked ( () -> {
        internalCreateItem (aItem);
      });
      LOGGER.info ("Added " + aItem.getLogText () + " to re-try list for retry #" + (aItem.getRetryCount () + 1));
    }
docs: Add a unique item to the list.
  
  @param aItem
  The item to be added. May not be <code>null</code>.
  @throws IllegalStateException
  If an item with the same ID is already contained