code: private Object toLogString(HttpRequestMessage httpRequest) {
          StringBuilder b = new StringBuilder();
          b.append(httpRequest.getRequestURI()).append('\n');
          final Map<String,List<String>> headers = httpRequest.getHeaders();
          for ( String h: headers.keySet()) {
              b.append(h).append(':').append(' ').append(headers.get(h)).append('\n');
          }
          return b.toString();
      }
docs: /* For logging and debugging only