DateTime objects with sub-millisecond timestamps are being rounded to the millisecond

[lukegeor]

If you run the code below, you'll see that the two lines written to the console are not the same. The DateTime is being rounded to the nearest millisecond.

DateTime d = new DateTime(123456789012);
Console.WriteLine(d.Ticks);
var serializer = new JsonSerializer();
byte[] buffer;

using (MemoryStream ms = new MemoryStream())
{
    using (BsonDataWriter w = new BsonDataWriter(ms))
    {
        serializer.Serialize(w, new List<DateTime>() { d });
        ms.Position = 0;
        buffer = ms.ToArray();
    }
}
using (MemoryStream ms = new MemoryStream(buffer))
{
    using (BsonDataReader r = new BsonDataReader(ms))
    {
        r.ReadRootValueAsArray = true;
        var d2 = (List<DateTime>)serializer.Deserialize(r, typeof(List<DateTime>));
        Console.WriteLine(d2[0].Ticks);
    }
}

[lukegeor]

Never mind. Looks like that's part of the BSON spec.