Create sequetial UUID

I got a lot of interesting answers for the riddle, and here is my solution:

private static int sequentialUuidCounter;
public static Guid CreateSequentialUuid()
{
   var ticksAsBytes = BitConverter.GetBytes(DateTime.Now.Ticks);
   Array.Reverse(ticksAsBytes);
   var increment = Interlocked.Increment(ref sequentialUuidCounter);
   var currentAsBytes = BitConverter.GetBytes(increment);
   Array.Reverse(currentAsBytes);
   var bytes = new byte[16];
   Array.Copy(ticksAsBytes, 0, bytes, 0, ticksAsBytes.Length);
   Array.Copy(currentAsBytes, 0, bytes, 12, currentAsBytes.Length);
   return bytes.TransfromToGuidWithProperSorting();
}

  Basically, we use the current system ticks as the 1 – 8 bytes, and a counter incremented atomically on the 12 – 16 bytes. This ensures that even concurrent calls on the same tick will have a different value.

Read more: Ayende @ Rahien

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