Function seal_in 

fn seal_in(
    drafts: &Path,
    memory: &Path,
    certs: &Certs<'_>,
    roots: &[PathBuf],
    cache: &Path,
    judged: &mut Judged,
) -> Sealed

seal_clear_drafts in these folders: the drafts’, the sharing’s memory (its history and what it kept before sharing began beside it), your mail (roots, its index of Message-IDs kept in cache). Each copy takes its place under the sharing’s exchange lock, a short hold at a time (share::replacements_hold): no exchange reads one while it is replaced.