PlainText property will return part of the message that
            has content-type of text/plain. It
            could be whole message, but also any of its parts.
            wodMailbox will search through all message parts until it
            finds text/plain part, and return
            it through this property.
            In specific occasions, if ContentType is
            multipart/mixed, wodMailbox will go
            one level deeper and check if any of parts have ContentType
            of multipart/alternative - in which
            case text/plain content will be
            searched among those parts. This is typical message with
            two parts (plaintext and html) and attachment.
            If plaintext content is encoded, wodMailbox will decode
            it before it returns it to you through this property.