Bug fix: Fix errorWidget on dart DDC (web)

[JustusFluegel]

✨ What kind of change does this PR introduce? (Bug fix, feature, docs update...)

Bug fix: The errorWidget would never be displayed when running using DDC (dart web) and the HttpGet option, which happens because the catch block currently never gets executed when using streams with await for on dart DDC.
As such this pr refactors the file to use a StreamController instead, re-implementing the original behavior.

⤵️ What is the current behavior?

Placeholder stays displayed even if a error response (e.g. 404) happened, when running using DDC

💥 Does this PR introduce a breaking change?

No, this is a pure bug fix.

🐛 Recommendations for testing

Maybe add a DDC test suite? idk

📝 Links to relevant issues/docs

• A catch block in an async* method does not catch exceptions from await for in DDC dart-lang/sdk#47764

🤔 Checklist before submitting

• All projects build
• Follows style guide lines (code style guide)
• Relevant documentation was updated
• Rebased onto current develop

[mitcoef]

I agree with this change. Even if the mentioned issue is fixed in the future, using the Stream class listen method is much more idiomatic and should thus be preferred regardless.

[martijn00]

@JustusFluegel can you fix the unit tests for this?

[JustusFluegel]

Will do that in the next few days, don't have the time to look at it right now :) Thanks for finally taking a look at this tho, appreciate you taking the time

[JustusFluegel]

So I've added a try catch which mirrors the old behavior of sending the UnimplementedError of trying to create the stream from the mock cache controller across the output stream as well - I don't know if this is the prettiest solution but it should be the one that mirrors the old code the closest. If you wish to do this in a different way, let me know :)