/// <summary>
 /// Dispose unmanaged resources and/or set large fields
 /// (managed/unmanaged) to null. This method will be called whether
 /// the <see cref="Disposable.Dispose()"/> method is called by the
 /// finalizer or your code.
 /// </summary>
 protected override void DisposeExtra()
 {
     _repo       = null;
     _unitOfWork = null;
 }