The AllHeaders property will return all of the RFC 822
header values in a string. This includes the message headers
that are most commonly referred to, such as the To, From and Subject
headers. Each header and its value are separated by a colon, and
terminated with a carriage return and linefeed (CRLF) pair.
The headers and their values returned by this property will not be
identical to the header block in the original message. If a header
value is split across multiple lines, the text returned by this
property will be folded, with the complete header value on a single
line of text and removing any extraneous whitespace. If the header
value has been encoded by the mail client, this property will return
the decoded value, not the original encoded value.