Function adopt 

fn adopt(
    dir: &Path,
    listed: &Listed,
    file: &str,
    mine: &str,
    (href, etag, data): (String, String, String),
    report: &mut Report,
) -> Result<ItemState, SyncError>

A new item here (file, holding mine) whose UID the server holds already under another address, theirs: that item takes its place, under its file, never sent again. An invitation answered on two devices: the same answers (agenda::answers), taken as it is; others, the server’s kept, and said (Report::answered): the organizer may have had both. An item without guests (a contact, a task) that differs: yours set aside first, as any item changed on both sides.