Unrecognized DataStoreHubEvent: outboxMutationFailed

[Lorenzohidalgo]

Describe the bug
There are some Events for DataStoreHubEvent that are not recognized and therefore cant be handled with a hubSubscription.

For some reason DataStore won't update a specific model and since the event is not recognized the only error log that I'm receiving is:
E/amplify:flutter:datastore(27989): Unrecognized DataStoreHubEvent: outboxMutationFailed

To Reproduce
Steps to reproduce the behavior:

1. Create a Flutter Project with DataStore
2. Make some CRUD operations
3. See error - some events are not recognized

Expected behavior
The event should be recognized or a detailed error description should be prompted to be able to debug the error.

Platform
Amplify Flutter currently supports iOS and Android. This issue is reproducible in (check all that apply):
[X] Android
[] iOS

Output of flutter doctor -v

[√] Flutter (Channel stable, 2.2.0, on Microsoft Windows [Versión 10.0.19042.985], locale es-ES)
  • Flutter version 2.2.0 at C:\DEVELOPMENT\SRC\flutter
  • Framework revision b22742018b (3 weeks ago), 2021-05-14 19:12:57 -0700
  • Engine revision a9d88a4d18
  • Dart version 2.13.0

[√] Android toolchain - develop for Android devices (Android SDK version 30.0.3) 
  • Android SDK at C:\Users\Lorenzo HG\AppData\Local\Android\sdk
  • Platform android-30, build-tools 30.0.3
  • Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java       
  • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)
  • All Android licenses accepted.

[√] Chrome - develop for the web
  • Chrome at C:\Program Files (x86)\Google\Chrome\Application\chrome.exe      

[√] Android Studio (version 4.1.0)
  • Android Studio at C:\Program Files\Android\Android Studio
  • 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 1.8.0_242-release-1644-b01)

[√] VS Code, 64-bit edition (version 1.56.2)
  • VS Code at C:\Program Files\Microsoft VS Code
  • Flutter extension version 3.23.0

[√] Connected device (3 available)
  • sdk gphone x86 (mobile) • emulator-5554 • android-x86    • Android 11 (API 30) (emulator)
  • Chrome (web)            • chrome        • web-javascript • Google Chrome 91.0.4472.77
  • Edge (web)              • edge          • web-javascript • Microsoft Edge 91.0.864.37

• No issues found!

Smartphone (please complete the following information):

• Device: Emulated Pixel 4
• OS: Android 11
• Version API30

[HuiSF]

OutboxMutationFailedEvent would be published when processing a mutation in the outbox went wrong. Currently the flutter library doesn't have a specific handling of this exception, therefore it logs it as "not recognized" error.

To be noted, OutboxMutationFailedEvent can have many different causes, it's unnecessarily an amplify-flutter library issue. But the library should forward this exception properly, to provide more meaningful exception information to consumer.

[b-cancel]

This is a bug report I just filed that includes a couple of bugs I found and the workarounds to each
after reading your bug report I think it could help
#822

[HuiSF]

With the latest release of amplify-flutter, it log will provide full details unhandled event instead of printing an error log.