GlowingOverscrollIndicator causes the blur effect of the BackdropFilter to be out of the range of the child widget

main.dart

import 'dart:ui' as ui;
import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: ScrollConfiguration(
        behavior: AlwaysGlowingOverscrolBehavior(),
        child: Scaffold(body: Container(color: Colors.white, child: Demo())),
      ),
    );
  }
}

class Demo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Stack(
      fit: StackFit.expand,
      children: <Widget>[
        Text(List.filled(10000, '0').join().toString(),
            style: TextStyle(color: Colors.black)),
        Positioned(
          top: 100.0,
          bottom: 100.0,
          left: 0.0,
          right: 0.0,
          child: BackdropFilter(
            filter: ui.ImageFilter.blur(
              sigmaX: 5.0,
              sigmaY: 5.0,
            ),
            child: Container(
              color: Colors.black.withOpacity(0.5),
              child: SingleChildScrollView(
                child: Column(
                  children: <Widget>[
                    Text(
                      'Top',
                      style: TextStyle(fontSize: 32.0, color: Colors.white),
                    ),
                    Container(
                      height: 1000.0,
                      alignment: Alignment.center,
                      child: Text(
                        'Center',
                        style: TextStyle(fontSize: 32.0, color: Colors.white),
                      ),
                    ),
                    Text(
                      'Bottom',
                      style: TextStyle(fontSize: 32.0, color: Colors.white),
                    ),
                  ],
                ),
              ),
            ),
          ),
        ),
      ],
    );
  }
}

class AlwaysGlowingOverscrolBehavior extends ScrollBehavior {
  @override
  Widget buildViewportChrome(
      BuildContext context, Widget child, AxisDirection axisDirection) {
    return GlowingOverscrollIndicator(
      child: child,
      axisDirection: axisDirection,
      color: Theme.of(context).accentColor,
    );
  }

  @override
  ScrollPhysics getScrollPhysics(BuildContext context) {
    return const ClampingScrollPhysics();
  }
}