Asynchronous intercept method of StreamInterceptor

Is it possible to implement promise- or callback- based `intercept` method of `StreamInterceptor` like the `UnaryInterceptor`? For example:

```ts
class StreamAuthInterceptor implements StreamInterceptor {
async intercept(
r: Request,
invoker: (r: Request) => ClientReadableStream
): Promise> {
r.getMetadata()['authorization'] = await getAuth();
return invoker(r);
}
}
```