pub fn boundary(headers: &RawHeaders) -> Option<Boundary>Expand description
Walking down from the top as written_on_arrival does, your provider’s
own hops passed (inside_hop), the first other line: where the message
came in, when the address its server saw reads (seen_ip) and is public.
A line written another way gives none: the lines below it are the
sender’s to write, so no address of theirs is taken for where it came in.