code: private <T> String writeMapValues(String mapName, MultiValueMap<T> map) {
          StringBuffer buffer = new StringBuffer();
          buffer.append("        " + mapName + "\n");
          for (Iterator<T> names = map.names(); names.hasNext();) {
              T name = names.next();
              buffer.append("            ").append(name.toString()).append("\n");
              String[] values = map.getStringArray(name);
              for (String element : values) {
                  buffer.append("                ").append(element).append("\n");
              }
          }
          return buffer.toString();
      }
docs: Helper for the {@link #log(ConsumerJournalEntry)} method. Writes the
  values of a context multi-map.