/// <summary>
 /// Add package loaders.
 /// </summary>
 /// <param name="options"></param>
 /// <param name="loaders"></param>
 /// <returns></returns>
 public static IPackageFileProviderOptions AddPackageLoaders(this IPackageFileProviderOptions options, IEnumerable <IPackageLoader> loaders)
 => options.SetPackageLoaders(options.PackageLoaders.Concat(loaders).ToArray());
 /// <summary>
 /// Add package loaders.
 /// </summary>
 /// <param name="options"></param>
 /// <param name="loaders"></param>
 /// <returns></returns>
 public static IPackageFileProviderOptions AddPackageLoaders(this IPackageFileProviderOptions options, params IPackageLoader[] loaders)
 => options.SetPackageLoaders(options.PackageLoaders.Concat(loaders).ToArray());
 /// <summary>
 /// Add package loader.
 /// </summary>
 /// <param name="options"></param>
 /// <param name="loader"></param>
 /// <returns></returns>
 public static IPackageFileProviderOptions AddPackageLoader(this IPackageFileProviderOptions options, IPackageLoader loader)
 => options.SetPackageLoaders(options.PackageLoaders.Concat(Enumerable.Repeat(loader, 1).ToArray()));