body_type_msg

# File lib/net/imap.rb, line 2542
      def body_type_msg
        mtype, msubtype = media_type
        match(T_SPACE)
        param, content_id, desc, enc, size = body_fields

        token = lookahead
        if token.symbol == T_RPAR
          # If this is not message/rfc822, we shouldn't apply the RFC822
          # spec to it.  We should handle anything other than
          # message/rfc822 using multipart extension data [rfc3501] (i.e.
          # the data itself won't be returned, we would have to retrieve it
          # with BODYSTRUCTURE instead of with BODY

          # Also, sometimes a message/rfc822 is included as a large
          # attachment instead of having all of the other details
          # (e.g. attaching a .eml file to an email)
          if msubtype == "RFC822"
            return BodyTypeMessage.new(mtype, msubtype, param, content_id,
                                       desc, enc, size, nil, nil, nil, nil,
                                       nil, nil, nil)
          else
            return BodyTypeExtension.new(mtype, msubtype,
                                         param, content_id,
                                         desc, enc, size)
          end
        end

        match(T_SPACE)
        env = envelope
        match(T_SPACE)
        b = body
        match(T_SPACE)
        lines = number
        md5, disposition, language, extension = body_ext_1part
        return BodyTypeMessage.new(mtype, msubtype,
                                   param, content_id,
                                   desc, enc, size,
                                   env, b, lines,
                                   md5, disposition, language, extension)
      end