Function owns_threads 

fn owns_threads(
    subscription: &SlackSubscription,
    conversation: &SlackConversation,
) -> bool

Whether this subscription wants a thread’s replies. Watching a conversation is not the same as wanting everything in it: a mentions-mode subscription asked to be told when it is named, and it is told through the match, so it owns no thread - or every thread the sweep anchors would deliver every reply to a session that asked for mentions. A Mentions target is swept by search and owns no conversation at all.