public async Task <IEnumerable <PackageName> > QueryPackages(string userName, PackageState packageState)
        {
            if (string.IsNullOrWhiteSpace(userName))
            {
                throw new ArgumentNullException("userName");
            }

            //materializing to avoid directory enumeration handles locking deletes
            return(LocalPackageStorageItem.Query(feedPath, userName, packageState).ToList());
        }
 public async Task <IEnumerable <PackageName> > QueryPackages(PackageState packageState)
 {
     return(LocalPackageStorageItem.Query(feedPath, packageState).ToList());
 }