# Download to file given resource
	fun download_to_file(output_file_name: nullable String): CurlResponse
	do
		if not self.curl.is_ok then return answer_failure(0, "Curl instance is not correctly initialized")

		var success_response = new CurlFileResponseSuccess

		var callback_receiver: CurlCallbacks = success_response
		if self.delegate != null then callback_receiver = self.delegate.as(not null)

		var err

		err = self.curl.native.easy_setopt(new CURLOption.follow_location, 1)
		if not err.is_ok then return answer_failure(err.to_i, err.to_s)

		err = self.curl.native.easy_setopt(new CURLOption.url, url)
		if not err.is_ok then return answer_failure(err.to_i, err.to_s)

		err = self.curl.native.register_callback_header(callback_receiver)
		if not err.is_ok then return answer_failure(err.to_i, err.to_s)

		err = self.curl.native.register_callback_stream(callback_receiver)
		if not err.is_ok then return answer_failure(err.to_i, err.to_s)

		var opt_name
		if not output_file_name == null then
			opt_name = output_file_name
		else if not self.url.substring(self.url.length-1, self.url.length) == "/" then
			opt_name = self.url.basename
		else
			return answer_failure(0, "Unable to extract file name, please specify one")
		end

		success_response.file = new FileWriter.open(opt_name)
		if not success_response.file.is_writable then
			return answer_failure(0, "Unable to create associated file")
		end

		var err_resp = perform
		if err_resp != null then return err_resp

		var st_code = self.curl.native.easy_getinfo_long(new CURLInfoLong.response_code)
		if not st_code == null then success_response.status_code = st_code

		var speed = self.curl.native.easy_getinfo_double(new CURLInfoDouble.speed_download)
		if not speed == null then success_response.speed_download = speed

		var size = self.curl.native.easy_getinfo_double(new CURLInfoDouble.size_download)
		if not size == null then success_response.size_download = size

		var time = self.curl.native.easy_getinfo_double(new CURLInfoDouble.total_time)
		if not time == null then success_response.total_time = time

		success_response.file.close

		return success_response
	end