This document defines a "digest" subtype of the "multipart" Content-
   Type.  This type is syntactically identical to "multipart/mixed", but
   the semantics are different.  In particular, in a digest, the default
   Content-Type value for a body part is changed from "text/plain" to
   "message/rfc822".  This is done to allow a more readable digest
   format that is largely compatible (except for the quoting convention)
   with RFC 934.

Note: Though it is possible to specify a Content-Type value for a body part in a digest which is other than "message/rfc822", such as a "text/plain" part containing a description of the material in the digest, actually doing so is undesireble. The "multipart/digest" Content-Type is intended to be used to send collections of messages. If a "text/plain" part is needed, it should be included as a seperate part of a "multipart/mixed" message.

A digest in this format might, then, look something like this:

     From: Moderator-Address
     To: Recipient-List
     Date: Mon, 22 Mar 1994 13:34:51 +0000
     Subject: Internet Digest, volume 42
     MIME-Version: 1.0
     Content-Type: multipart/mixed;
                   boundary="---- main boundary ----"

     ------ main boundary ----

       ...Introductory text or table of contents...

     ------ main boundary ----
     Content-Type: multipart/digest;
                   boundary="---- next message ----"

     ------ next message ----

     From: someone-else
     Date: Fri, 26 Mar 1993 11:13:32 +0200
     Subject: my opinion

       ...body goes here ...

     ------ next message ----

     From: someone-else-again
     Date: Fri, 26 Mar 1993 10:07:13 -0500
     Subject: my different opinion

       ... another body goes here ...

     ------ next message ------

     ------ main boundary ------