code: @Override
      public HttpMessage get(int index) {
          try {
              return historyReferences.get(index).getHttpMessage();
          } catch (HttpMalformedHeaderException | DatabaseException e) {
              if (LOGGER.isDebugEnabled()) {
                  LOGGER.debug("Failed to get the message from DB: " + e.getMessage(), e);
              }
          }
          return null;
      }
docs: {@inheritDoc}
  <p>
  <strong>Note:</strong> The returned message will be {@code null} if an error occurred while loading the message from the
  database (for example, no longer exists).