docs: private final void _writeCallback(Persistable persistable) throws IOException 
      {
          if (_callbackToItem)
          {
              try
              {
                  String className = persistable.getItemClassName();
                  AbstractItem item = (AbstractItem) (Class.forName(className).newInstance());
                  List<DataSlice> dataSlices = _persistentMessageStore.readDataOnly(persistable);
                  if (dataSlices != null)
                  {
                      item.restore(dataSlices);
                      item.xmlWriteOn(_writer);
                  }
              }
              catch (IOException ioexc)
              {
                  // No FFDC code needed
                  // as this is fault diagnostic code, and the exception 
                  // will be dumped to the output anyway
                  _writer.write(ioexc);
                  throw ioexc;
              }
              catch (Throwable t)
              {
                  // No FFDC code needed
                  // as this is fault diagnostic code, and the exception 
                  // will be dumped to the output anyway
                  _writer.write(t);
              }
          }
      }