async Task UploadContentAsync(IHasId book, BookContent content, UploadTask task)
{
var names = GetFileNames(book, content);
var array = task.EnumerateFiles().ToArray();
for (var i = 0; i < array.Length; i++)
{
var(_, s, m) = array[i];
await _storage.WriteAsync(new StorageFile
{
Name = names[i],
Stream = s,
MediaType = m
});
}
}