I think the "end-of-body delimiter" they're talking about is the MIME
end-of-body, not CRLF. That is, if it's a multipart message, the
end-of-body is CRLF then two hyphens then the boundary parameter then
perhaps two more hyphens then another CRLF. If it's base64 encoded, it
would be the blank line at the end of the encoding. And so on.