code: static List<HpackHeader> createHeaders(int numHeaders, int nameLength, int valueLength,
                                             boolean limitToAscii) {
          List<HpackHeader> hpackHeaders = new ArrayList<HpackHeader>(numHeaders);
          for (int i = 0; i < numHeaders; ++i) {
              byte[] name = randomBytes(new byte[nameLength], limitToAscii);
              byte[] value = randomBytes(new byte[valueLength], limitToAscii);
              hpackHeaders.add(new HpackHeader(name, value));
          }
          return hpackHeaders;
      }
docs: Creates a number of random headers with the given name/value lengths.