anchor.diff:  class Television {
     Television({
       this.host,
  -    this.port: 12549,
  +    this.port: 10002,
       this.username,
       this.password,
  -    this.onError,
     }) {
       assert(port != null);
     }
  
positive.code:   final int port;
    final String username;
    final String password;
    final ErrorHandler onError;
  
    Socket _socket;
    StreamIterator<String> _responses;
  
negative.code:       socket.encoding = UTF8;
        socket.write('$username\x0d$password\x0d');
        await socket.flush();
        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);
  