public function addHttpHeader($http_header, $value)
    {
        $field = EnumRequestOption::HTTP_HEADERS;
        $http_headers = isset($this->options[$field]) ? $this->options[$field] : [];

        foreach($http_headers as $key => $header){
            if (strpos($header, $http_header) === 0){
                $http_headers[$key] = "$http_header: $value\r\n";
                return;
            }
        }

        $http_headers[$http_header] = $value;
        $this->options[$field] = $http_headers;
    }