Function get_all_addresses_from_header

fn get_all_addresses_from_header(
    headers: &[MailHeader<'_>],
    header: &str,
) -> Vec<SingleInfo>

Extracts all addresses from the header named header.

If multiple headers with the same name are present, the last one is taken. This is because DKIM-Signatures apply to the last headers, and more headers may be added to the beginning of the messages without invalidating the signature unless the header is “oversigned”, i.e. included in the signature more times than it appears in the mail.