How to close this stream ?

        async Task<StorageFile> CropImage(StorageFile storageFile, ImageCropper imageCropper)
        {
            var copiedStorageFile = await storageFile.CopyAsync(ApplicationData.Current.TemporaryFolder, storageFile.Name, NameCollisionOption.ReplaceExisting);
            using (var fileStream = await copiedStorageFile.OpenAsync(FileAccessMode.ReadWrite, StorageOpenOptions.None))
            {
                await imageCropper.SaveAsync(fileStream, BitmapFileFormat.Png);
            }
            return copiedStorageFile;
        }