Sends a SMTP 'RCPT' command. - Indicates a recipient for the e-mail.

        For further details, please check out `RFC 5321 § 4.1.1.3`_ and
        `§ 3.3`_.

        Args:
            recipient (str): E-mail address of one recipient.
            options (list of str or None, optional): Additional options to send
                along with the *RCPT* command.

        Raises:
            ConnectionResetError: If the connection with the server is
                unexpectedely lost.
            SMTPCommandFailedError: If the RCPT command fails.

        Returns:
            (int, str): A (code, message) 2-tuple containing the server
                response.

        .. _`RFC 5321 § 4.1.1.3`: https://tools.ietf.org/html/rfc5321#section-4.1.1.3
        .. _`§ 3.3`: https://tools.ietf.org/html/rfc5321#section-3.3

async def rcpt(self, recipient, options=None):
        """
        Sends a SMTP 'RCPT' command. - Indicates a recipient for the e-mail.

        For further details, please check out `RFC 5321 § 4.1.1.3`_ and
        `§ 3.3`_.

        Args:
            recipient (str): E-mail address of one recipient.
            options (list of str or None, optional): Additional options to send
                along with the *RCPT* command.

        Raises:
            ConnectionResetError: If the connection with the server is
                unexpectedely lost.
            SMTPCommandFailedError: If the RCPT command fails.

        Returns:
            (int, str): A (code, message) 2-tuple containing the server
                response.

        .. _`RFC 5321 § 4.1.1.3`: https://tools.ietf.org/html/rfc5321#section-4.1.1.3
        .. _`§ 3.3`: https://tools.ietf.org/html/rfc5321#section-3.3
        """
        if options is None:
            options = []

        to_addr = "TO:{}".format(quoteaddr(recipient))
        code, message = await self.do_cmd("RCPT", to_addr, *options)

        return code, message