docs: public String debugInfo(Object key) {
        EntryPosition entry = temporaryTable.get(key);
        if (entry != null) {
           return "temporaryTable: " + entry;
        } else {
           try {
              entry = index.getPosition(key, marshaller.objectToByteBuffer(key));
              return "index: " + entry;
           } catch (Exception e) {
              log.debugf(e, "Cannot debug key %s", key);
              return "exception: " + e;
           }
        }
     }