public function addMeta($key, $data = null)
    {
        if (is_array($key)) {
            $this->meta += $key;
        } else {
            $this->meta[$key] = $data;
        }

        return $this;
    }
public function addMeta($key, $data = null)
    {
        if (is_array($key)) {
            $this->meta += $key;
        } else {
            $this->meta[$key] = $data;
        }

        return $this;
    }
public function addMeta ( $ key , $ data = null ) { if ( is_array ( $ key ) ) { $ this -> meta += $ key ; } else { $ this -> meta [ $ key ] = $ data ; } return $ this ; }
add additional meta data to transformed data.

@param $key
@param $data

@return $this
add additional meta data to transformed data .