docs: private static List<String> exploreALPN(ByteBuffer input,
              int extLen) throws SSLException {
          final ArrayList<String> strings = new ArrayList<>();
  
          int rem = extLen;
          if (extLen >= 2) {
              int listLen = getInt16(input);
              if (listLen == 0 || listLen + 2 != extLen) {
                  throw UndertowMessages.MESSAGES.invalidTlsExt();
              }
  
              rem -= 2;
              while (rem > 0) {
                  int len = getInt8(input);
                  if (len > rem) {
                      throw UndertowMessages.MESSAGES.notEnoughData();
                  }
                  byte[] b = new byte[len];
                  input.get(b);
                  strings.add(new String(b, StandardCharsets.UTF_8));
  
                  rem -= len + 1;
              }
          }
          return strings.isEmpty() ? Collections.emptyList() : strings;
      }