From: aperson@dom.ain
To: bperson@dom.ain
Subject: Test
Content-Type: multipart/mixed; boundary="BOUNDARY"

MIME message
--BOUNDARY
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit

One
--BOUNDARY
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit

Two
--BOUNDARY--
End of MIME message