GetResult uses AddMilliseconds instead of AddSeconds for expiry

#if NETSTANDARD2_1

 _expiryTime = DateTime.UnixEpoch.AddMilliseconds(ms).ToLocalTime();

#else

 var unixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);

 _expiryTime = unixEpoch.AddSeconds(ms).ToLocalTime();

#endif

#if (NETSTANDARD || NETCOREAPP) && !NETSTANDARD2_0

 _expiryTime = DateTime.UnixEpoch.AddMilliseconds(ms).ToLocalTime();

#else

 var unixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);

 _expiryTime = unixEpoch.AddMilliseconds(ms).ToLocalTime();

#endif