using System;

​

public class Program

{

    public static void Main()

    {

        //Some epoch time in ms

        var gmail_date = 1512007768005;

        //Get DateTime of epoch ms

        var to_date = DateTimeOffset.FromUnixTimeMilliseconds(gmail_date).DateTime;

        //This is your timezone offset GMT +8

        var offset = 8;

        Console.WriteLine(to_date - new TimeSpan(offset * -1, 0, 0));

    }

}