public function collStats() : Stage\CollStats
    {
        $stage = new Stage\CollStats($this);
        $this->addStage($stage);

        return $stage;
    }
public function collStats() : Stage\CollStats
    {
        $stage = new Stage\CollStats($this);
        $this->addStage($stage);

        return $stage;
    }
public function collStats ( ) : Stage \ CollStats { $ stage = new Stage \ CollStats ( $ this ) ; $ this -> addStage ( $ stage ) ; return $ stage ; }
Returns statistics regarding a collection or view.

$collStats must be the first stage in an aggregation pipeline, or else
the pipeline returns an error.

@see http://docs.mongodb.org/manual/reference/operator/aggregation/collStats/
Returns statistics regarding a collection or view .