[[!comment format=mdwn
 username="joey"
 subject="""comment 4"""
 date="2021-10-27T18:40:48Z"
 content="""
Aha, that makes sense! addurl constructs a url-based Key to use while
downloading, and the key transfer machinery prevents redundant downloads
of the same Key at the same time.

Arguably, the problem is not where the message gets put, but that
it fails when adding an url to two different paths at the same time.

I have, though, moved that message so it will appear in error-messages.
"""]]
