How to scroll only the scrollbar not the screen in flutter

Question

How to scroll only the scrollbar not the screen in the flutter

So I have this problem, I want to work on the scrollbar scrolling only not the entire screen of this.

Thank you!

here is the sample of my code

  Widget build(BuildContext context) {
    return Scaffold(
      appBar: MySecondRoundedAppbar("TEST"),
      body: Scrollbar(
        
          child: SingleChildScrollView(
        
        child: Column(
          children: [
            
            Padding(
              padding: const EdgeInsets.symmetric(vertical: 10, horizontal: 30),
              child: Row(
                children: [
                  
                 
                  Expanded(
                    child: FlatButton(
                      child: Text("test"),
                      color: color4,
                      onPressed: () {
                        
                      },
                    ),
                  ),
                  SizedBox(
                    width: 10,
                  ),
                  Expanded(
                    child: FlatButton(
                      child: Text("test"),
                      color: color4,
                      onPressed: () {
                       
                      },
                    ),
                  )
                ],
              ),
            )
          ],
        ),
      )),
    );
  }