DetailLoaderWithProgressItem.cs

public class DetailLoaderWithProgressItem<T> : IDetailLoader<T>
{ 
    private IDetailLoader<T> _loader; 
    private ProgressItem _progressItem; 

    public DetailLoaderWithProgressItem(IDetailLoader<T> loader, ProgressItem progressItem) 
    { 
        _loader = loader; 
        _progressItem = progressItem; 
    }

    public void Load(string importPath, Action<T> addToBatch) 
    { 
        _loader.Load(importPath, addToBatch); 
        _progressItem.EndWithSuccess(); 
    }

    public IEnumerable<T> GetDetailItems(IEnumerable<Row> rows) 
    { 
        _progressItem.Start(rows.Count()); 
        return _loader.GetDetailItems(rows); 
    }

    public T GetDetailItemFrom(Row row) 
    { 
        _progressItem.IncrementProgress(); 
        return _loader.GetDetailItemFrom(row); 
    } 
}