public Task <Customer> GetCustomerAsync(ICustomerDataLoader customerDataLoader, int id, CancellationToken cancellationToken) => customerDataLoader.LoadAsync(id, cancellationToken);
public Task <IReadOnlyList <Customer> > GetCustomersByIdsAsync( ICustomerDataLoader customerDataLoader, List <int> ids, CancellationToken cancellationToken) => customerDataLoader.LoadAsync(ids, cancellationToken);