public static async Task <IReadOnlyCollection <T> > FindByListOfKeysAsync <T, TKey>(
this IQueryableRepository <T> source,
IEnumerable <TKey> keys,
CancellationToken cancellationToken = default) where T : IKey <TKey> where TKey : IEquatable <TKey>
{
cancellationToken.ThrowIfCancellationRequested();
return(await source.ProcessQueryAsync(
source.AsQueryable()
.Where(item => keys.Contains(item.Id)), cancellationToken));
}