code: public function withoutHeader($header)
      {
          $header = strtolower($header);
          $response = clone $this;
          $response->headers = array_filter($this->headers, function ($key) use ($header) {
              return $key !== $header;
          }, ARRAY_FILTER_USE_KEY);
  
          return $response;
      }
docs: {@inheritdoc}