Function journal_send 

pub(crate) fn journal_send<K, V>(
    priority: Priority,
    msg: &str,
    vars: impl Iterator<Item = (K, V)>,
)
where
    K: AsRef<str>,
    V: AsRef<str>,

Wrapper for structured logging which is an explicit no-op when systemd is not in use (e.g. in a container).