JsonGenerator jgen, SerializerProvider provider,
TypeSerializer typeSer)
throws IOException, JsonGenerationException
{
final ObjectIdWriter w = _objectIdWriter;
WritableObjectId oid = provider.findObjectId(bean, w.generator);
Object id = oid.id;
if (id != null) { // have seen before; serialize just id
oid.serializer.serialize(id, jgen, provider);
return;