using System;

using System.Linq;

using System.Collections.Generic;

using System.Collections;

public class Program

{

    public static void Main()

    {

        PerformGuidIncrements(10);

        PerformGuidIncrements(100);

        PerformGuidIncrements(1000);

        PerformGuidIncrements(4081);

        PerformGuidIncrements(4082);

    }

    private static void PerformGuidIncrements(int by){

        var guids = Enumerable.Range(0, by).Select(i => Guid.Empty.Increment(i));

        Console.WriteLine($"No duplicates after {by} increments: {guids.Count() == guids.Distinct().Count()}");

    }

}

​

public static class GuidExtensions{

​

    public static Guid Increment(this Guid guid, int by = 1)

        {

            var guidBytes = guid.ToByteArray();

​

            for (var i = 0; i < by; i++)

            {

                guidBytes = SingleIncrement(guidBytes);

            }

​

            return new Guid(guidBytes);

        }

        private static byte[] SingleIncrement(byte[] guidBytes)

        {

            var byteMaxCounter = 0;

            for (var i = 15; i >= 0; i--)

            {

                if (guidBytes[i] == 255)

                {

                    byteMaxCounter++;

                    continue;

                }

                guidBytes[i]++;

                break;

            }

​

            if (byteMaxCounter < 16) return guidBytes;

            var result = Enumerable.Repeat(byte.MinValue, 16).ToArray();

            result[15]++;

            return result;

​

        }

}