/// <summary>
        /// Add a new message.
        /// </summary>
        public void AddMessageWarning(string content, string title = null)
        {
            var message = new FeedbackMessage(FeedbackMessageType.Warning, content, title);

            AddMessage(message);
        }
        /// <summary>
        /// Add a new message.
        /// </summary>
        public void AddMessageSuccess(string content, string title = null)
        {
            var message = new FeedbackMessage(FeedbackMessageType.Success, content, title);

            AddMessage(message);
        }
        /// <summary>
        /// Add a new message.
        /// </summary>
        public void AddMessageError(string content, string title = null)
        {
            var message = new FeedbackMessage(FeedbackMessageType.Error, content, title);

            AddMessage(message);
        }
        /// <summary>
        /// Add a new message.
        /// </summary>
        public void AddMessageInfo(string content, string title = null)
        {
            var message = new FeedbackMessage(FeedbackMessageType.Info, content, title);

            AddMessage(message);
        }
 /// <summary>
 /// Adds a message instance.
 /// </summary>
 private void AddMessage(FeedbackMessage message)
 {
     _messages.Add(message);
 }