From: from@example.com
To: to@example.com
Date: Fri, 21 Nov 1997 09:55:06 -0600
Subject: This is the subject
Content-Type: multipart/alternative; boundary=bound

--bound
Content-Transfer-Encoding: base64
Remark: Content is "hello world" with no newline

aGVsbG8gd29ybGQ=

--bound
Content-Transfer-Encoding: base64
Remark: Content is "hell\0 w\0rld" with no newline

aGVsbAAgdwBybGQ=

--bound--