/// <summary>
        ///   <para>The size of the rendered button.</para>
        /// </summary>
        /// <param name="widget">Widget to call method on.</param>
        /// <param name="size">Size of button.</param>
        /// <returns>Reference to provided <paramref name="widget"/>.</returns>
        /// <exception cref="ArgumentNullException">If <paramref name="widget"/> is a <c>null</c> reference.</exception>
        /// <seealso cref="ITwitterTweetButtonWidget.Size(string)"/>
        public static ITwitterTweetButtonWidget Size(this ITwitterTweetButtonWidget widget, TwitterTweetButtonSize size)
        {
            Assertion.NotNull(widget);

            return(widget.Size(size.ToString().ToLowerInvariant()));
        }
    /// <summary>
    ///   <para>The size of the rendered button.</para>
    /// </summary>
    /// <param name="widget">Widget to call method on.</param>
    /// <param name="size">Size of button.</param>
    /// <returns>Reference to provided <paramref name="widget"/>.</returns>
    /// <exception cref="ArgumentNullException">If <paramref name="widget"/> is a <c>null</c> reference.</exception>
    /// <seealso cref="ITwitterTweetButtonWidget.Size(string)"/>
    public static ITwitterTweetButtonWidget Size(this ITwitterTweetButtonWidget widget, TwitterTweetButtonSize size)
    {
      Assertion.NotNull(widget);

      return widget.Size(size.ToString().ToLowerInvariant());
    }