(per RFC2660)

Media Type name: message

Media subtype name: s-http

Required parameters: none

Optional parameters: version, msgtype

  version: The S-HTTP version number of the enclosed message
  (e.g. "1.4"). If not present, the version can be
        determined from the first line of the body.

  msgtype: The message type -- "request" or "response".
        If not present, the type can be determined from the
        first line of the body.

Encoding considerations: only "7bit", "8bit", or "binary"
     are permitted.

Security considerations: this is a security protocol.

Intended Usage: OBSOLETE