Null exception error when item is downloaded

I have lots of errors due to null exceptions. These kinds of mistakes are troublesome for me that app in production.

Flutter version: `2.10.0`
package version: `1.7.2`

** Errors**:
```
Fatal Exception: java.lang.NullPointerException
Attempt to read from field 'java.lang.String tc.b.b' on a null object reference
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io.flutter.embedding.engine.loader.FlutterLoader.findAppBundlePath (FlutterLoader.java:390)
vn.hunghd.flutterdownloader.DownloadWorker.startBackgroundIsolate (DownloadWorker.java:122)
vn.hunghd.flutterdownloader.DownloadWorker.access$000 (DownloadWorker.java:67)
vn.hunghd.flutterdownloader.DownloadWorker$1.run (DownloadWorker.java:111)
```
```
W[/System.err]()( 8192): java.lang.NullPointerException: Attempt to read from field 'boolean vn.hunghd.flutterdownloader.DownloadTask.resumable' on a null object reference
W[/System.err]()( 8192): at vn.hunghd.flutterdownloader.DownloadWorker.downloadFile(DownloadWorker.java:457)
W[/System.err]()( 8192): at vn.hunghd.flutterdownloader.DownloadWorker.doWork(DownloadWorker.java:235)
```

**Flutter doctor**:
```
[✓] Flutter (Channel stable, 2.10.0, on macOS 12.2 21D49 darwin-x64, locale en-TR)
• Flutter version 2.10.0 at /Users/kaantahakoken/fvm/versions/2.10.0
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision 5f105a6ca7 (6 days ago), 2022-02-01 14:15:42 -0800
• Engine revision 776efd2034
• Dart version 2.16.0
• DevTools version 2.9.2

[✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
• Android SDK at /Users/kaantahakoken/Library/Android/sdk
• Platform android-31, build-tools 31.0.0
• ANDROID_HOME = /Users/kaantahakoken/Library/Android/sdk
• ANDROID_SDK_ROOT = /Users/kaantahakoken/Library/Android/sdk
• Java binary at: /Applications/Android Studio.app/Contents/jre/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7281165)
• All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 13.2.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• CocoaPods version 1.11.2

[✓] Chrome - develop for the web
• Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2020.3)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7281165)

[✓] VS Code (version 1.64.0)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.34.0

[✓] Connected device (2 available)
• Mi 9T (mobile) • c22e6ace • android-arm64 • Android 11 (API 30)
• Chrome (web) • chrome • web-javascript • Google Chrome 98.0.4758.80
! Error: iPhone0 is not connected. Xcode will continue when iPhone is connected. (code -13)

[✓] HTTP Host Availability
• All required HTTP hosts are available

• No issues found!
```