Httpful post form data

finally I found the answer, thanks to @Xiquid that guide me to find the answer, here is my working answer for sending post data using php httpful rest client :

$google_redirect = $request->getSchemeAndHttpHost().$this->generateUrl('myroutename')."?platform=google"; 
        $url =  "https://www.googleapis.com/oauth2/v3/token";

        $data =  array(
            'code'          => $request->query->get('code'),
            'client_id'     => $this->container->getParameter('GOOGLE_CLIENT_ID'),
            'client_secret' => $this->container->getParameter('GOOGLE_CLIENT_SECRET'),
            'redirect_uri'  => $google_redirect,
            'grant_type'    => "authorization_code"
        );


        $response = RestRequester::post($url)
                ->method(Http::POST)        // Alternative to Request::post
                ->withoutStrictSsl()        // Ease up on some of the SSL checks
                ->expectsJson()             // Expect HTML responses
                ->sendsType(Mime::FORM)

                ->body('grant_type=authorization_code&code='.$data['code']."&client_id=".$data['client_id']."&client_secret=".$data['client_secret']."&redirect_uri=".$data['redirect_uri'])
                ->send();

        var_dump($response);
        die();