Integrate with WebAssembly multithreading

[SteveSandersonMS]

As multithreading is added to the core .NET WebAssembly runtime, we need to ensure this doesn't lead to invalid/dangerous scenarios for Blazor components.

• Min bar: if the renderer is accessed from the wrong thread, throw
• Ideal: sync context with semantics equivalent to Blazor Server or WebView, so InvokeAsync works

This is going to come in late so we should take a risk-averse position on how much we attempt to implement here.

[pavelsavara]

Related dotnet/runtime#86759

[mkArtakMSFT]

@MackinnonBuck, @pavelsavara is there any remaining work here for our team, or should this be closed already?

[pavelsavara]

this needs core review #48991

[mkArtakMSFT]

@lewing, @pavelsavara, @maraf at this point, given all the other other critical issues on our plate, I've moved this out of .NET 8 release.

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 9 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.