public static void Main()
var unixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
var ts1 = new BsonTimestamp(6715363589873467395);
var target1 = unixEpoch.AddSeconds(ts1.Timestamp - 18000);
Console.WriteLine(target1.ToUniversalTime());
var ts2 = new BsonTimestamp(6494541724705095681);
var target2 = unixEpoch.AddSeconds(ts2.Timestamp - 18000);
Console.WriteLine(target2.ToUniversalTime());