Amp\Artax\Client::generateRawRequestHeaders PHP Method

    private function generateRawRequestHeaders(Request $request)
    {
        $uri = $request->getUri();
        $uri = new Uri($uri);
        $requestUri = $uri->getPath() ?: '/';
        if ($query = $uri->getQuery()) {
            $requestUri .= '?' . $query;
        }
        $str = $request->getMethod() . ' ' . $requestUri . ' HTTP/' . $request->getProtocol() . "\r\n";
        foreach ($request->getAllHeaders() as $field => $valueArr) {
            foreach ($valueArr as $value) {
                $str .= "{$field}: {$value}\r\n";
            }
        }
        $str .= "\r\n";
        return $str;
    }