public void FromMillisecondsString_SummerTime()
        {
            TimeZoneInfo romance = TimeZoneInfo.FindSystemTimeZoneById("Romance Standard Time");

            DateTimeOffset resultUtc     = UnixTimeUtils.FromMilliseconds("1629182100123");
            DateTimeOffset resultDenmark = TimeZoneInfo.ConvertTime(resultUtc, romance);

            Assert.AreEqual("2021-08-17T06:35:00.123+00:00", resultUtc.ToString("yyyy-MM-ddTHH:mm:ss.fffK"));
            Assert.AreEqual("2021-08-17T08:35:00.123+02:00", resultDenmark.ToString("yyyy-MM-ddTHH:mm:ss.fffK"));
        }
        public void FromMillisecondsString_NormalTime()
        {
            TimeZoneInfo romance = TimeZoneInfo.FindSystemTimeZoneById("Romance Standard Time");

            DateTimeOffset resultUtc     = UnixTimeUtils.FromMilliseconds("1643886000123");
            DateTimeOffset resultDenmark = TimeZoneInfo.ConvertTime(resultUtc, romance);

            Assert.AreEqual("2022-02-03T11:00:00.123+00:00", resultUtc.ToString("yyyy-MM-ddTHH:mm:ss.fffK"));
            Assert.AreEqual("2022-02-03T12:00:00.123+01:00", resultDenmark.ToString("yyyy-MM-ddTHH:mm:ss.fffK"));
        }