class method self.convert_to

# File actionmailer/lib/action_mailer/vendor/tmail-1.2.7/tmail/quoting.rb, line 139
        def convert_to(text, to, from)
          return text unless to && from
          text ? Iconv.iconv(to, from, text).first : ""
        rescue Iconv::IllegalSequence, Iconv::InvalidEncoding, Errno::EINVAL
          # the 'from' parameter specifies a charset other than what the text
          # actually is...not much we can do in this case but just return the
          # unconverted text.
          #
          # Ditto if either parameter represents an unknown charset, like
          # X-UNKNOWN.
          text
        end