In flutter how to open bottom sheet above bottom bar

Question

I am using https://pub.dev/packages/persistent_bottom_nav_bar package to show bottom bar. I need to open bottom sheet when one of the bottom bar tab pressed. I have managed to show bottom sheet using showModalBottomSheet, but problem is it covers existing bottom bar. I need to open bottom sheet above bottom bar instead of from bottom of screen. This is what i want to achieve.

So I managed to show using showGeneralDialog with Container and bottom margin. Below is my solution.

showGeneralDialog(
        barrierLabel: AppLocalizations.of(context).translate(LanguageConstant.more),
        barrierDismissible: true,
        barrierColor: Colors.grey.withOpacity(0.1),
        transitionDuration: Duration(milliseconds: 100),
        context: context,
        pageBuilder: (dialogContext, anim1, anim2) {
          return Align(
            alignment: Alignment.bottomCenter,
            child: Container(
              margin: EdgeInsets.only(bottom: CommonConstants.BOTTOM_BAR_HEIGHT, top: MediaQuery.of(context).size.height/2, left: 0, right: 0),
              decoration: BoxDecoration(
                  color: Theme.of(context).colorScheme.surface,
                  border: Border.all(width: 0.5,color: ColorConstants.blackShade3),
              ),
              child: <Your child widgets>,
            ),
          );
        },
        transitionBuilder: (dialogContext, anim1, anim2, child) {
          return SlideTransition(
            position: Tween(begin: Offset(0, 1), end: Offset(0, 0)).animate(anim1),
            child: child,
          );
        },
      );