public void SerializeProperty(
BsonWriter bsonWriter,
object obj,
BsonPropertyMap propertyMap
)
{
var value = (BsonObjectId) propertyMap.Getter(obj);
if (value == null) {
bsonWriter.WriteNull(propertyMap.ElementName);
} else {
bsonWriter.WriteObjectId(propertyMap.ElementName, value.Timestamp, value.MachinePidIncrement);
}
}