@Override
    public long skip(final long n) throws IOException {
        throw new UnsupportedOperationException();
    }
Returns a formatted TCP-info element, depending on the success of the IP
address name resolution either with domain name or only the address literal.

@param host the address of the remote SMTP client.
@return the formatted TCP-info element as defined by RFC 5321
src/main/java/de/gessnerfl/fakesmtp/smtp/io/ReceivedHeaderStream.java