Change FaultAction to support async logic

[jonnepmyra]

Is your feature request related to a problem? Please describe.

I’d like to suggest a change to the FaultAction delegate. Right now, it returns a ChunkAction directly, which means I can't easily run asynchronous logic inside the handler (e.g., closing the consumer.).

The current delegate is defined as something like:
Func<IConsumer, ChunkAction> FailAction { get; init; }

This makes it impossible to await anything inside the function.

Describe the solution you'd like

Change the delegate to support async operations by returning a Task:

Func<IConsumer, Task<ChunkAction>> FailAction { get; init; }

This would allow users to await async code without workarounds like blocking on async calls.

Describe alternatives you've considered

No response

Additional context

No response