Function create_feed 

pub fn create_feed(
    conn: &Connection,
    user_id: Option<&str>,
    name: &str,
    kinds: &[String],
    include_account_names: bool,
) -> Result<(FeedRecord, String), String>

Mints a feed. Returns the record and the plaintext token — the only time the plaintext exists outside the requester’s own response.