/// <summary>
        /// Creates an audit writer and logs the success.
        /// </summary>
        /// <param name="filterContext">The current filter context to get the user and the action.</param>
        protected void AuditSuccess(ControllerContext filterContext)
        {
            var audit = this.Audit ?? (this.Audit = this.CreateAudit());

            if (audit == null)
            {
                return;
            }

            filterContext.ArgumentMustNotBeNull("filterContext");
            audit.AuthenticationCheckSucceeded(new AuditInfo <Exception>(filterContext.RequestContext));
        }