code: public function retrieveHeaders(): array
      {
          $this->setHeader('Connection', 'close');
          $this->setHeader('Accept', '');
          $this->setHeader('Accept-Language', '');
          $this->setHeader('User-Agent', '');
          
          $savedProto = $this->protocol;
          $this->protocol = 'HTTP/1.0';
          $this->request('HEAD');
          $this->protocol = $savedProto;
          
          return $this->getHeaders();
      }
docs: Load headers from remote and return it
  
  @return array