Widget _buildButton() {
    return Row(
      mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        Padding(
          padding: const EdgeInsets.only(right: 8.0),
          child: RaisedButton.icon(
            icon: Icon(Icons.call),
            onPressed: addCall,
            label: Text("Add Call"),
          ),
        ),
        RaisedButton.icon(
          icon: Icon(Icons.call_made),
          onPressed: endCall,
          label: Text("End Random Call"),
        )
      ],
    );
  }