DevTools extensions do not load for offline use cases by default. Requires solution + documentation.

Stack trace:
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<-- Please describe your problem here. Be sure to include repro steps. -->

I'm working on a DevTools extension,[^2] I initially managed to get my UI to show up, following the steps over here,[^1] then this error started appearing randomly:

Clicking that link brought me here (although as you can see it was unable to populate a stack trace...)

I couldn't really find anything useful in the console, the only 2 errors I noted were the following, with DevTools being unable to find some source maps and some Google Analytics thing not being loaded:

I initially thought this was due to some use of `log` inside my code, but I realised that even without it my basic example wouldn't work...

Then, I realised the one difference from yesterday is the rather poor Internet connection I have right now (thank you Swiss Railways... ), and indeed, after the extension did load (as said, the error is random), I saw this:

It appears that some files are being loaded both from localhost and from some Google CDN (at least the names are the same). And the timing appears to match the delay I see when loading the UI.

Moving over to my mobile connection, suddenly everything worked fine.

Opening the DevTools from Chrome or Safari made no difference.

Is this expected? Did I build the extension UI incorrectly so that it fetches some data remotely?

Thanks!

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**DevTools version**: 2.31.0
**IDE**: IntelliJ-IDEA
**Connected Device**:
CPU / OS: Web macos
Connected app type: Flutter web (debug build)
Dart Version: 3.3.0-279.3.beta
Flutter Version: 3.19.0-0.4.pre / beta
Framework / Engine: b7e7d46a04 / 98820f0a77

[^1]: https://medium.com/flutter/dart-flutter-devtools-extensions-c8bc1aaf8e5f
[^2]: https://github.com/borgoat/daredux

Reproduce the DevTools extension setup from the linked extension example while offline or on a poor connection, and inspect the remote requests, source-map failures, and analytics errors shown in the report. Done means extensions load reliably without network access and the required offline behavior or setup is documented.

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