code: public void dropByIndex(int idx) {
      SAXRecord entry = realTSindex.get(idx);
      if (null != entry) {
        realTSindex.remove(idx);
        entry.removeIndex(idx);
        if (entry.getIndexes().isEmpty()) {
          records.remove(String.valueOf(entry.getPayload()));
        }
      }
    }
docs: Drops a single entry.
  
  @param idx the index.