Doctrine\ODM\MongoDB\PersistentCollection::changed PHP Method

    private function changed()
    {
        if ( ! $this->isDirty) {
            $this->isDirty = true;
            if ($this->dm && $this->mapping !== null && $this->dm->getClassMetadata(get_class($this->owner))->isChangeTrackingNotify()) {
                $this->dm->getUnitOfWork()->scheduleForDirtyCheck($this->owner);
            }
        }
    }