/// <summary>
 /// Adds or replaces an extension.
 /// </summary>
 /// <typeparam name="T">The type of extension to be stored.</typeparam>
 /// <param name="extension">The extension instance.</param>
 public void AddOrReplaceExtension <T>(T extension)
     where T : class
 {
     Options.AddOrReplaceExtension(extension);
 }