/// <summary>
        /// Get an <see cref="IMailService"/> instance.
        /// </summary>
        /// <returns>
        /// An existing <see cref="IMailService"/> instance if available; otherwise a fresh instance.
        /// </returns>
        public IMailService GetMailService()
        {
            if (this.mailService == null)
            {
                this.mailService = new MailService(modId, mailManager);

                mailManager.RegisterMailSender(modId, mailService);
            }

            return(mailService);
        }