Struct.new(:media_type, :subtype, :param, :content_id, :description, :encoding, :size, :lines, :md5, :disposition, :language, :extension)
Net::IMAP::BodyTypeText represents TEXT body structures of messages.
Returns the size of the body in text lines.
And Net::IMAP::BodyTypeText has all fields of Net::IMAP::BodyTypeBasic.