Status response message as carrier for annotations as alternative to 204 No Content

There are some situations where OData 4.0 requires a response with 204 No Content:
1. GET a raw primitive value using the /$value path suffix and the value is null
2. GET a nullable property or navigation property and the value is null
3. DELETE a nullable property or relationship to set it to null
4. GET a function result that is primitive or structured and is null
5. POST an action call and the primitive or structured result is null, or the action has no result

This does not allow to add explanatory annotations to the logically empty result.