From: John Smith <john@example.com>
MIME-Version: 1.0
Subject: =?UTF-8?B?0J/RgNC+0LLQtdGA0LrQsA==?=
To: Mark Smith <mark@example.com>
Bcc: Anna Smith <anna@example.com>
Cc: Luis Smith <luis@example.com>
Content-Type: multipart/mixed;
        boundary="XXXXboundary text"; foo

This is a multipart message in MIME format.

--XXXXboundary text
Content-Type: text/plain

this is the body text

--XXXXboundary text
Content-Type: text/plain;
Content-Disposition: attachment;
        filename="test.txt"

this is the attachment text

--XXXXboundary text--
