ThreadHelpers is a class, that contains few methods to simplify development of multithread programs.

ThreadHelpers

using System;
using System.Threading;

namespace Konard.Helpers
{
    public static class ThreadHelpers
    {
        public const int BarrierDefaultValue = int.MinValue;

        public static void InitializeThreadBarrier(ref int barrier)
        {
            barrier = ThreadHelpers.BarrierDefaultValue;
        }

        public static void OnlyFirstThreadCanContinue(ref int barrier)
        {
            int result = Interlocked.CompareExchange(ref barrier, Thread.CurrentThread.ManagedThreadId, ThreadHelpers.BarrierDefaultValue);
            if (barrier != Thread.CurrentThread.ManagedThreadId)
                throw new Exception("Only first thread can continue execution.");
        }
    }
}