/// <summary>
        /// Default constructor.
        /// </summary>
        /// <param name="responseLine">SMTP server response line.</param>
        /// <exception cref="ArgumentNullException">Is raised when <b>responseLine</b> is null.</exception>
        public SMTP_ClientException(string responseLine) : base(responseLine.TrimEnd())
        {
            if (responseLine == null)
            {
                throw new ArgumentNullException("responseLine");
            }

            m_pReplyLines = new SMTP_t_ReplyLine[] { SMTP_t_ReplyLine.Parse(responseLine) };
        }