public function getResponseHeader($key, $first = true): string
    {
        $header = $this->response->getHeader($key);
        $headerFirst = $header[0] ?? '';
        return $first ? $headerFirst : $header;
    }
public function getResponseHeader($key, $first = true): string
    {
        $header = $this->response->getHeader($key);
        $headerFirst = $header[0] ?? '';
        return $first ? $headerFirst : $header;
    }
public function getResponseHeader ( $ key , $ first = true ) : string { $ header = $ this -> response -> getHeader ( $ key ) ; $ headerFirst = $ header [ 0 ] ?? '' ; return $ first ? $ headerFirst : $ header ; }
Returns specific response header defined by key

@param      $key
@param bool $first

@return string
Returns specific response header defined by key