PathProvider.getApplicationDocumentsDirectory sometimes returns null #6359

import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  runApp(
    new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new FlutterDemo(),
    ),
  );
}

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

  @override
  _FlutterDemoState createState() => new _FlutterDemoState();
}

class _FlutterDemoState extends State<FlutterDemo> {
  Future printAppDir() async {
    Directory appDir = await PathProvider.getApplicationDocumentsDirectory();
    print(appDir?.path ?? "null appDir");
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
        appBar: new AppBar(
          title: new Text('Flutter Demo'),
        ),
        body: new Column(children: [
          new RaisedButton(
              child: new Text("print app dir"), onPressed: printAppDir),
        ]));
  }
}

Users/drewwarren/Library/Developer/CoreSimulator/Devices/16BCCC3C-2F9C-401F-B2BF-97F1E3D2929A/data/Containers/Data/Application/A3252D13-A6D7-4B9F-8563-A339446A1E43/Documents
/Users/drewwarren/Library/Developer/CoreSimulator/Devices/16BCCC3C-2F9C-401F-B2BF-97F1E3D2929A/data/Containers/Data/Application/A3252D13-A6D7-4B9F-8563-A339446A1E43/Documents
null appDir
/Users/drewwarren/Library/Developer/CoreSimulator/Devices/16BCCC3C-2F9C-401F-B2BF-97F1E3D2929A/data/Containers/Data/Application/A3252D13-A6D7-4B9F-8563-A339446A1E43/Documents
null appDir
null appDir
null appDir
null appDir
null appDir
/Users/drewwarren/Library/Developer/CoreSimulator/Devices/16BCCC3C-2F9C-401F-B2BF-97F1E3D2929A/data/Containers/Data/Application/A3252D13-A6D7-4B9F-8563-A339446A1E43/Documents
/Users/drewwarren/Library/Developer/CoreSimulator/Devices/16BCCC3C-2F9C-401F-B2BF-97F1E3D2929A/data/Containers/Data/Application/A3252D13-A6D7-4B9F-8563-A339446A1E43/Documents
null appDir

[✓] Flutter (on Mac OS, channel master)
    • Flutter at /Users/drewwarren/flutter
    • Framework revision 3203757958 (52 minutes ago), 2016-10-17 10:30:13
    • Engine revision d999f6c123
    • Tools Dart version 1.20.1

[x] Android toolchain - develop for Android devices
    x Android Studio / Android SDK not found. Download from https://developer.android.com/sdk/
      (or visit https://flutter.io/setup/#android-setup for detailed instructions).

[✓] iOS toolchain - develop for iOS devices (Xcode 7.3.1)
    • XCode at /Applications/Xcode.app/Contents/Developer
    • Xcode 7.3.1, Build version 7D1014

[✓] Atom - a lightweight development environment for Flutter
    • flutter plugin version 0.2.5
    • dartlang plugin version 0.6.39

[-] IntelliJ IDEA Community Edition (version 2016.2)
    • Dart plugin not installed; this adds Dart specific functionality.
    • Flutter plugin not installed; this adds Flutter specific functionality.
    • For information about managing plugins, see
      https://www.jetbrains.com/help/idea/2016.2/managing-plugins.html

[✓] Connected devices
    • iPhone 5s • 16BCCC3C-2F9C-401F-B2BF-97F1E3D2929A • ios (simulator)