docs: private static void exploreTLSRecord(
              ByteBuffer input, byte firstByte, byte secondByte,
              byte thirdByte, List<String> alpnProtocols, ByteArrayOutputStream out) throws SSLException {
  
          // Is it a handshake message?
          if (firstByte != 22) {        // 22: handshake record
              throw UndertowMessages.MESSAGES.notHandshakeRecord();
          }
  
          // Is there enough data for a full record?
          int recordLength = getInt16(input);
          if (recordLength > input.remaining()) {
              throw new BufferUnderflowException();
          }
          if(out != null) {
              out.write(0);
              out.write(0);
          }
  
          // We have already had enough source bytes.
          try {
              exploreHandshake(input,
                  secondByte, thirdByte, recordLength, alpnProtocols, out);
          } catch (BufferUnderflowException ignored) {
              throw UndertowMessages.MESSAGES.invalidHandshakeRecord();
          }
      }