Consider renaming "asyncIterator" to "register"

From a first glance of the signature

```
asyncIterator(triggers: string | string[]): AsyncIterator;
```

Seems it's more like a `register` method to add one or more event names to listen to, does it make sense to consider renaming it to just that?

Start by reviewing the public TypeScript signature shown in the issue and the surrounding subscription API to determine whether asyncIterator is intended as a registration method. Done means reaching a naming decision and, if approved, updating the exposed API consistently with its callers and tests.

Written by the indexing model from the issue text.