David Kean

Set a breakpoint in https://github.com/dotnet/project-system/blob/master/src/Microsoft.VisualStudio.ProjectSystem.Managed.VS/ProjectSystem/VS/References/DesignTimeAssemblyResolution.cs, this should be returning "mscorlib".

Grab a binlog of the ResolveAssemblyReferences call that shows it missing, it might be an SDK bug.

Oh, thinking about this a little more - it might not be an SDK bug, it might be our bug. There's a built-in assumption that all references show up in...

VB build is different, I think IRC it picks it up from the sdk path that is passed to it. We do not want behavior differences between design-time builds and...

Yes that's what operation progress is solving.

tag @drewnoakes

@CyrusNajmabadi?

@SabotageAndi We found a bunch more stacks and they all in AppInsightsAnalyticsTransmitterSink.TransmitEvent, so be sure to find all direct and indirect callers of it.

Sorry Steve, I missed your reply to this. > It seems like this would be effective if there were two threads going into the same Lazy initializer but that doesn't...

Feel free to close it out - I'll open another bug with more traces if this continues to appear in our GC pause data.