I was trying to look at why flutter/plugins#3828 failed the Windows CI, and there's pretty much no way to tell. It seems that there are a few issues here, likely all related:

• It looks like it probably timed out for some reason rather than returning failure; it's extremely unlikely that this build actually took an hour.
• The stdout page never seems to finish loading. I've had a spinner there for several minutes.
• The useful part of the output isn't there; the last message is that it was going to start the build that would be failing here, but none of the actual build output.

This feels very similar to the recent issue where flutter packages get or pub get resolver failures timeout without useful output rather than just failing.