Some plinq examples

Program.cs

using System;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;

namespace ParallelTest
{
    class Program
    {
        static void Main(string[] args)
        {
            RunTests();
            Console.ReadLine();
        }

        private static async void RunTests()
        {
            await Test(ToListExample, "ToListExample");
            await Test(NoToListExample, "NoToListExample");
            await Test(NoParallelExample, "NoParallelExample");
        }

        private static async Task<int> NoParallelExample()
        {
            var result =
                await Task.WhenAll(Enumerable
                    .Range(0, 100)
                    .Select((_, index) => WorkWorkWork(index)));
            var sum = result.Sum();
            return sum;
        }

        private static async Task<int> ToListExample()
        {
            var result =
                await Task.WhenAll(Enumerable
                    .Range(0, 100)
                    .AsParallel()
                    .Select((_, index) => WorkWorkWork(index))
                    .ToList());
            var sum = result.Sum();
            return sum;
        }

        private static async Task<int> NoToListExample()
        {
            var result =
                await Task.WhenAll(Enumerable
                    .Range(0, 100)
                    .AsParallel()
                    .Select((_, index) => WorkWorkWork(index)));
            var sum = result.Sum();
            return sum;
        }

        private static async Task Test(Func<Task<int>> target, string sampleTest)
        {
            var sw = new Stopwatch();
            sw.Start();
            var sum = await target();
            Console.WriteLine($"Sum: {sum}");
            sw.Stop();
            Console.WriteLine($"{sampleTest} took {sw.ElapsedMilliseconds} ms");
        }
        private static async Task<int> WorkWorkWork(int i)
        {
            await Task.Delay(1000);
            return i;
        }
    }
}

@kahole, you're completely right so I updated the sample. I'm more used to F# way of dealing with async, which doesn't stark the execution until you actually ask for the result.