Blazor Web App takes a long time to shut down when pressing Ctrl-C

[danroth27]

Repro steps:

• Install .NET 9 or .NET 10 Preview 2
• dotnet new blazor
• dotnet run
• Browse to the counter page of the app
• Shut down the app using Ctrl-C

Expected result: App shuts down immediately and the browser displays the reconnect dialog

Actual result: The app logs "Application is shutting down...", but then it takes a long time for the app to shut down and for the reconnect dialog to show up.

[KainTim]

I am experiencing this as well on dotnet 9, so I am not entirely sure that these Issues are related.

[danroth27]

I am experiencing this as well on dotnet 9, so I am not entirely sure that these Issues are related.

@KainTim Thanks for the feedback! I'm also now able to reproduce this with .NET 9.

[davidfowl]

@BrennanConroy sounds like SignalR

[BrennanConroy]

Dupe of #58947 and https://github.com/dotnet/AspNetCore-ManualTests/issues/3139#issuecomment-2480121793