anchor.diff:    static const int SyncIdentifier = 83;
     static const int PasswordIdentifier = 112;
   
  -  int get length;
  -
  -  void applyStringToBuffer(UTF8BackedString string, ByteDataWriter buffer) {
  -    buffer.write(string.utf8Bytes);
  -    buffer.writeInt8(0);
  -  }
  -
  -  void applyBytesToBuffer(List<int> bytes, ByteDataWriter buffer) {
  -    buffer.write(bytes);
  -  }
  -
     void applyToBuffer(ByteDataWriter buffer);
   
     Uint8List asBytes() {
  
positive.code:   }
  }
  
  class StartupMessage extends ClientMessage {
    final UTF8BackedString _username;
    final UTF8BackedString _databaseName;
  
negative.code:         _username = username == null ? null : UTF8BackedString(username);
  
    @override
    void applyToBuffer(ByteDataWriter buffer) {
      final fixedLength = 53;
      final variableLength = (_username?.utf8Length ?? 0) +
          _databaseName.utf8Length +
          _timeZone.utf8Length +
          3;
  
      buffer.writeInt32(fixedLength + variableLength);
      buffer.writeInt32(ClientMessage.ProtocolVersion);
  
      if (_username != null) {
        buffer.write(UTF8ByteConstants.user);
        _applyStringToBuffer(_username, buffer);
      }
  
      buffer.write(UTF8ByteConstants.database);
      _applyStringToBuffer(_databaseName, buffer);
  
      buffer.write(UTF8ByteConstants.clientEncoding);
      buffer.write(UTF8ByteConstants.utf8);
  
      buffer.write(UTF8ByteConstants.timeZone);
      _applyStringToBuffer(_timeZone, buffer);
  
      buffer.writeInt8(0);
    }
  