有没有办法在flutter charts_flutter中垂直放置标签文本：^0.8.1

dependencies:
  flutter:
    sdk: flutter
  charts_flutter: ^0.8.1

import 'package:flutter/material.dart';
import 'package:charts_flutter/flutter.dart' as charts;

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Charts Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        appBar: AppBar(
          title: Text('Flutter Charts Demo'),
        ),
        body: Center(
          child: Container(
            height: 300,
            padding: EdgeInsets.all(16),
            child: charts.BarChart(
              _createSampleData(),
              animate: true,
              barRendererDecorator: charts.BarLabelDecorator(
                labelAnchor: charts.BarLabelAnchor.end,
                labelPosition: charts.BarLabelPosition.inside,
                labelPadding: 4,
                outsideLabelStyleSpec: charts.TextStyleSpec(
                  fontSize: 12,
                  color: charts.MaterialPalette.white,
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }

  List<charts.Series<OrdinalSales, String>> _createSampleData() {
    final data = [
      OrdinalSales('2014', 5),
      OrdinalSales('2015', 25),
      OrdinalSales('2016', 100),
      OrdinalSales('2017', 75),
    ];

    return [
      charts.Series<OrdinalSales, String>(
        id: 'Sales',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: data,
      ),
    ];
  }
}

class OrdinalSales {
  final String year;
  final int sales;

  OrdinalSales(this.year, this.sales);
}