Make transfer-04 show how callbacks work #384
Description
Feature Request
Currently sample transfer-04 shows how to implement a custom listener, but that's a bit low level detail, the sample should show how the callbacks mechanism is working:
ref. https://eclipse-edc.github.io/documentation/for-contributors/runtime/service-layers/#6-events-and-callbacks
Which Areas Would Be Affected?
e.g., DPF, CI, build, transfer, etc.
Why Is the Feature Desired?
Are there any requirements?
Who will sponsor this feature?
Please @-mention the committer that will sponsor your feature.
Solution Proposal
If possible, provide a (brief!) solution proposal.