private function scheduleForInsert($object)
    {
        $oid = spl_object_hash($object);
        $class = $this->manager->getClassMetadata(get_class($object));

        $this->documentInsertions[$oid] = $object;

        if (null !== $class->getSingleIdentifier($object)) {
            $this->addToIdentityMap($object);
        }
    }