public String toString() {
    StringBuilder buf = new StringBuilder();
    List<String> names = names();
    for (int i = 0; i < names.size(); i++) {
      List<String> values = _getValues(names.get(i));
      for (int j = 0; j < values.size(); j++) {
        buf.append(names.get(i))
            .append("=")
            .append(values.get(j))
            .append(" ");
      }
    }
    return buf.toString();
  }
Returns the HTTP headers as a plain Java map object. The map keys are
the header names and map values are the header content.

@return headers data as plain Java map.
crawler-commons/src/main/java/achecrawler/crawler/crawlercommons/util/Headers.java