Legend 
  | Field: Func<HttpRequest, HttpResponse> DirectoryListingAuth
 DeclarationFunc<HttpRequest, HttpResponse> DirectoryListingAuthSummaryIf directory listings are permitted, this handler is invoked to confirm that listing this specific directory is permitted. The handler should returnnull to allow directory listing, or an appropriate response if
                listing is not allowed. A null handler is identical to a handler that always returns null. |