Runtime Async is a new .NET 11 feature that requires architecture specific enablement.

Design document: https://github.com/dotnet/runtime/blob/main/docs/design/coreclr/botr/runtime-async-codegen.md

• https://github.com/dotnet/runtime/tree/main/src/tests/async tests passing with JIT
• NativeAOT support (including Hijacking changes for runtime async #122492)
• ...

Look for references to this issue number throughout the repo