Function shows 

pub fn shows(
    posted: &Posted,
    extra: &Extra,
    hash: &str,
    since: i64,
    before: bool,
) -> bool

Whether a notification shows a reply’s words as the person’s own (its hash, words_hash), as Signal and Element add your reply; the phone then says “shown”. A message of yours in the conversation (no sender, or the conversation’s own user) timed after the reply was taken (since, the phone’s clock, a second’s slack); where the notification gives no time, its words there, or in what went through its Reply lately (Extra::history), only when they were not there already before the reply (before, shown_already): an earlier “Oui” of yours never makes a later “Oui” shown.