Describe the bug

The long-lived circuits of Blazor server make distributed tracing not work as expected.

Since each circuit is effectively a long-lived request ... a lot of activity (pun intended) ends up getting traced under the same activity. Basically all outgoing requests/traces from inside of a Blazor server circuit (browser tab) will have the same parent span, which causes them to all get grouped together as a single "root cause" in tracing UIs.

To Reproduce

Create a Blazor server application. Use a button to fire off HTTP requests to another ASP.NET Core endpoint. Hook all of this up to your favorite distributed tracing system and enjoy.

All of the operations you start from a Blazor circuit will end inside the same single logical operation from a tracing POV.