Jumpt to offset messes up the headers.

I created a new flutter project and added

> sticky_headers:

Afterwards I implemented a list builder that has a ScrollController.
I call setState 3 times at a 5 seconds interval and modify a global offset variable which will be used on the build method to jump the list to a new offset (using SchedulerBinding.instance.addPostFrameCallback).

The problem is that after I call the jumpto method, the headers are messed up ( if I manual scroll the headers will come back to a normal position).

**Example:**


**The code:**
```
import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart';
import 'package:sticky_headers/sticky_headers.dart';

double offset = 0;

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

class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}

class MyHomePage extends StatefulWidget {
MyHomePage({Key key}) : super(key: key);

@override
_MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State {

ScrollController _scrollController = ScrollController();

@override
void initState() {
super.initState();
Future.delayed(Duration(seconds: 5)).then((_) => setState(() {
offset = 3000;
})).then((_) async => await Future.delayed(Duration(seconds: 5))).then((_) => setState(() {
offset = 1000;
})).then((_) async => await Future.delayed(Duration(seconds: 5))).then((_) => setState(() {
offset = 5000;
}));
}

@override
Widget build(BuildContext context) {
SchedulerBinding.instance.addPostFrameCallback((_) {
print(offset);
_scrollController.jumpTo(offset);
});
return Scaffold(body: Container(padding: EdgeInsets.only(top: 20),child: _buildList(context)));
}

Widget _buildList(BuildContext context) {
return NotificationListener(
child: ListView.builder(
controller: _scrollController,
itemCount: 100,
itemBuilder: (BuildContext context, int sectionIndex) => StickyHeader(
header: Container(
height: 50,
alignment: Alignment.center,
color: Colors.blue,
child: Text("$sectionIndex")),

content: ListView.builder(
itemCount: 10,
shrinkWrap: true,
physics: NeverScrollableScrollPhysics(),
itemBuilder: (context, rowIndex) => Container(
color: Colors.white,
child: Text("$sectionIndex"))))),

onNotification: (ScrollNotification scrollNotification) {
offset = _scrollController.offset;
print(offset);
return true;
});
}
}
```