трепетание приподнятой кнопкой тень

RaisedButton(child: Text("Rock & Roll"),
                onPressed: _changeText,
                color: Colors.red,
                textColor: Colors.yellow,
                padding: EdgeInsets.fromLTRB(10, 10, 10, 10),
                splashColor: Colors.grey,
              )
Puzzled Pheasant