Intercept and modify data

Thanks for the sample!

Is there a way to modify the data after interception?

E.g.,

```
...{intercept: true });
event.data.body = "abc"
event.helper.done() // Should return "abc" but does not
```

Or to have an equivalent of `event.helper.fail()` that does not trigger a notification? (e.g., `event.helper.fail({silent: true})`)