What is the equivalent of a call to drupal_http_request()?
Finally i find a code in https://api.drupal.org/api/drupal/core%21includes%21install.core.inc/8 (1375)

and its working for me :) 

 try {
    $response = \Drupal::httpClient()-&gt;get($uri, array('headers' =&gt; array('Accept' =&gt; 'text/plain')));
    $data = (string) $response-&gt;getBody();
    if (empty($data)) {
      return FALSE;
    }
  }
  catch (RequestException $e) {
    return FALSE;
  }


Hope this will help for some one