public function withSize($index, $value)
    {
        $res = clone $this;

        $res->sizes = $this->insertInList($res->sizes, $index, $value);

        return $res;
    }
public function withSize($index, $value)
    {
        $res = clone $this;

        $res->sizes = $this->insertInList($res->sizes, $index, $value);

        return $res;
    }
public function withSize ( $ index , $ value ) { $ res = clone $ this ; $ res -> sizes = $ this -> insertInList ( $ res -> sizes , $ index , $ value ) ; return $ res ; }
Set time fragment size, adding null values if needed.

@param integer      $index
@param integer|null $value
Set time fragment size adding null values if needed .