Repository: flutter
Issue: [video_player] Better exception message on iOS devices if the video fails to play
Labels: platform-ios,customer: crowd,p: video_player,package,a: error message,has reproducible steps,P2,found in release: 3.10,found in release: 3.11,team-ios,triaged-ios

## Steps to Reproduce

<!-- You must include full steps to reproduce so that we can reproduce the problem. -->

1. Create an application on iOS with the [video_player](https://pub.dev/packages/video_player)
2. Use a server which does not support [HTTP range header](https://developer.mozilla.org/en-US/docs/Web/HTTP/Range_requests)
3. Try to play a video on said server. It throws an `PlatformException(VideoError, Failed to load video: Operation Stopped, null)` exception with no further details.

**Expected results:** 
I would expect a better error message as iOS seems to be capable of giving a better error message.
See for example [this stackoverflow post](https://stackoverflow.com/questions/33493662/avplayeritem-status-avplayerstatusfailed-when-playing-video).

**Actual results:**
`PlatformException(VideoError, Failed to load video: Operation Stopped, null)`
with no further details why it throws this exception.

<details>
  <summary>Logs</summary>

`flutter analyze`

```
Analyzing zkb-app...                                                    
No issues found! (ran in 6.6s)
```

`flutter doctor -v`

```
[✓] Flutter (Channel stable, v1.17.0, on Mac OS X 10.15.4 19E287, locale de-DE)
    • Flutter version 1.17.0 at /Applications/flutter
    • Framework revision e6b34c2b5c (6 days ago), 2020-05-02 11:39:18 -0700
    • Engine revision 540786dd51
    • Dart version 2.8.1

 
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at /Users/user/Library/Android/sdk
    • Platform android-29, build-tools 29.0.2
    • Java binary at: /Users/user/Library/Application Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/192.6392135/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b4-5784211)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 11.3.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 11.3.1, Build version 11C504
    • CocoaPods version 1.8.4

[✓] Android Studio (version 3.6)
    • Android Studio at /Users/user/Library/Application Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/192.6392135/Android Studio.app/Contents
    • Flutter plugin version 45.1.1
    • Dart plugin version 192.7761
    • Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b4-5784211)

[!] IntelliJ IDEA Ultimate Edition (version 2020.1.1)
    • IntelliJ at /Users/user/Applications/JetBrains Toolbox/IntelliJ IDEA Ultimate.app
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
    • For information about installing plugins, see
      https://flutter.dev/intellij-setup/#installing-the-plugins

[✓] VS Code (version 1.44.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.9.1

[!] Connected device
    ! No devices available

! Doctor found issues in 2 categories.
```

</details>

I guess [this line and the following code](https://github.com/flutter/plugins/blob/master/packages/video_player/video_player/ios/Classes/FLTVideoPlayerPlugin.m#L258) should be expanded.