Error handler for async functions

Hello!

The README shows a [error handler](https://github.com/GoogleCloudPlatform/functions-framework-python/blob/a07b1e4f81d84424189488022e5f3d59c06014cc/examples/cloud_run_async/README.md) for the standard functions framework.

```py
import functions_framework

@functions_framework.errorhandler(ZeroDivisionError)
def handle_zero_division(e):
return "I'm a teapot", 418

def function(request):
1 / 0
return "Success", 200
```

Is there something similar available for the newer [async functions](https://github.com/GoogleCloudPlatform/functions-framework-python/blob/a07b1e4f81d84424189488022e5f3d59c06014cc/examples/cloud_run_async/README.md)?