Function warn_if_topics_scheduled 

pub(crate) fn warn_if_topics_scheduled(
    scheduled: &HashSet<String>,
    new_topics: &mut [String],
)

Warns the user if any of the new topics being subscribed to are already scheduled for unsubscription.

This function checks if any of the new topics being subscribed to are already scheduled for unsubscription. If so, it logs a warning message with the list of topics that are already scheduled.