anchor.diff:        socket.encoding = UTF8;
         socket.write('$username\x0d$password\x0d');
         await socket.flush();
  -      responses = new StreamIterator<String>(_socket.transform(UTF8.decoder).transform(const LineSplitter()));
  +      responses = new StreamIterator<String>(socket.transform(UTF8.decoder).transform(const LineSplitter()));
         await responses.moveNext();
         if (responses.current != 'Login:')
           throw new TelevisionException('did not get login prompt', responses.current, this);
  
positive.code:   final int port;
    final String username;
    final String password;
    final ErrorHandler onError;
  
    Socket _socket;
    StreamIterator<String> _responses;
  
negative.code: class Television {
    Television({
      this.host,
      this.port: 10002,
      this.username,
      this.password,
    }) {
      assert(port != null);
    }
  