It did not work correctly, since it assumed that 'lt::torrent_plugin' is created at an earlier stage and is able to track all changes in the torrent state, but in reality it turned out that it was created after the torrent moved to the `downloading_metadata` state, so we had to additionally handle it in the constructor.
PR #16121.
"private" subfolders violate the structure of the project,
since the existence of all other subfolders is based on a
different principle.
In addition, there is no clear line between "private" and
"non private".
