using System.Threading.Tasks;
public static void Main()
var random = new Random();
var lines = Enumerable.Range(0, 1000).Select(item => random.Next(0, 1000)).ToArray();
Parallel.For(0, pages, (int currentPage) =>
Console.WriteLine($"page {++i} of {pages}");
foreach (var line in lines.Skip(250 * currentPage).Take(pagesPerLine))
Console.WriteLine(total);