From foo@bar Thu Sep 13 10:34:44 2012
Return-path: <foo@bar>
Envelope-to: foi@example.org
Delivery-date: Thu, 13 Sep 2012 10:34:44 +0100
From: foo@bar
To: foi@example.org
Subject: an acknowledgement email
Date: Thu, 13 Sep 2012 10:08:03 +0100
Message-ID: <987654@foo.local>
Content-Type: multipart/mixed; boundary="-----7D81B75CCC90D2974F7A1CBD"

This is a multi-part message in MIME format.
-------7D81B75CCC90D2974F7A1CBD
Content-Type: text/html

<div>
  <p>
    This is an acknowledgement of your email, that irritatingly
    leaves out the final MIME boundary.
  </p>
<div>