Problem description

callback can be used for asynchronous response as in Population Density API or PredictiveConnectivityData where the response may need more time for computation and can contain large data chunk.

The standard behaviour of the API is synchronous, although for large
    area requests the API may behave asynchronously. An API invoker can enforce
    asynchronous behaviour by providing a callback URL (`sink`)
    is in the request, in this case the API sends a callback
    to the callback URL provided with the result of the request. 

sink and sinkCredential are defined as in CAMARA API Event Subscription and Notification Guide

Current guidelines distinguishes:

• Instance-based subscription (implicit creation) - a subscription indirectly created, additionally to another resource creation
• Resource-based subscription (explicit creation) - an event subscription managed as a resource

CAMARA event notification leverages CloudEvents

Expected action

Clarification on using CloudEvents as callback payload structure for asynchronous responses.
Should synchronous response include response object and asynchronous response response object embedded in CloudEvents structure?

Additional context

Overhead added by CloudEvents structure:

{
  "specversion": "1.0",
  "type": "org.camaraproject...",
  "source": "...",
  "id": "...",
  "time": "2025-09-17T10:30:00Z",
  "datacontenttype": "application/json",
  "data": {

  }
}

Question initially raised in #297 but not resolved.