it is possible to remove the animation in app bar back button?

Question

I create app bar to my flutter app, its work perfectly but i figure out that theres animation when i pressed the back button in app bar. the problem is when i pressed the back button in app bar it closed but its like sliding the context from top to bottom. i would like when i pressed the back button theres no animation there. how can you guys help me?

Im not yet try anything codes

AppBar(
        title: Text('Sample'),
        leading: IconButton(
          onPressed: () {
            Navigator.pop(context);
          },
          icon: Icon(Icons.navigate_before),
        ),
      ),

Thanks. Drew