Repository: flutter
Issue: [local_auth] `Fatal Exception: java.lang.IllegalStateException: Reply already submitted`
Labels: c: crash,platform-android,p: local_auth,package,P2,team-android,triaged-android

## Steps to Reproduce

Sorry, we are having problems reproducing this issue. We only have our testers that tell us, that it crashes sometimes and we have the Crashlytics logs to back it up. As I understood it, the app crashes, after the user used their biometric authentification method. Here is the stack trace: 

```
Fatal Exception: java.lang.IllegalStateException: Reply already submitted
       at io.flutter.embedding.engine.dart.DartMessenger$Reply.reply(DartMessenger.java:35)
       at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler$1.a(MethodChannel.java:14)
       at io.flutter.plugins.localauth.LocalAuthPlugin$1.a(LocalAuthPlugin.java:20)
       at io.flutter.plugins.localauth.AuthenticationHelper.a(AuthenticationHelper.java:30)
       at androidx.biometric.BiometricPrompt$1.lambda$onClick$0(BiometricPrompt.java:29)
       at androidx.biometric.-$$Lambda$BiometricPrompt$1$P30oSr_4In3G9QZQRdzDDZj8niU.run(-.java:2)
       at android.os.Handler.handleCallback(Handler.java:873)
       at android.os.Handler.dispatchMessage(Handler.java:99)
       at android.os.Looper.loop(Looper.java:214)
       at android.app.ActivityThread.main(ActivityThread.java:7050)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)
```

And another one (A tiny bit different):

```
Fatal Exception: java.lang.IllegalStateException: Reply already submitted
       at io.flutter.embedding.engine.dart.DartMessenger$Reply.reply(DartMessenger.java:35)
       at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler$1.a(MethodChannel.java:14)
       at io.flutter.plugins.localauth.LocalAuthPlugin$1.onSuccess(LocalAuthPlugin.java:20)
       at io.flutter.plugins.localauth.AuthenticationHelper.a(AuthenticationHelper.java:2)
       at androidx.biometric.BiometricFragment$1.a(BiometricFragment.java:17)
       at androidx.biometric.-$$Lambda$BiometricFragment$1$5yETAGvseQK65JiDb9XeeUnfaZA.run(-.java:4)
       at android.os.Handler.handleCallback(Handler.java:873)
       at android.os.Handler.dispatchMessage(Handler.java:99)
       at android.os.Looper.loop(Looper.java:214)
       at android.app.ActivityThread.main(ActivityThread.java:7050)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)
```


<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
[✓] Flutter (Channel stable, 1.22.6, on macOS 11.2 20D64 darwin-x64, locale en-GB)
    • Flutter version 1.22.6 at /[...]/flutter
    • Framework revision 9b2d32b605 (4 weeks ago), 2021-01-22 14:36:39 -0800
    • Engine revision 2f0af37152
    • Dart version 2.10.5

 
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
    • Android SDK at /[...]/Library/Android/sdk
    • Platform android-30, build-tools 30.0.2
    • Java binary at: /[...]/Library/Application Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/201.7042882/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 12.4)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.4, Build version 12D4e
    • CocoaPods version 1.10.0

[!] Android Studio (version 4.1)
    • Android Studio at /[...]/Library/Application Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/201.7042882/Android Studio.app/Contents
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)

 
[✓] Connected device (2 available)            
    • iPhone (mobile)            • [...] • ios • iOS 14.4
    • iPhone 12 Pro Max (mobile) • 55CBAC7D-BEF8-44D7-9F18-0CBA985B8D3C     • ios • com.apple.CoreSimulator.SimRuntime.iOS-14-4 (simulator)
```
 (Plugins are actually installed. No idea, why it says they aren't.)