title: How can I add proxy with IP/port and username/password in CurlHttpClient on Symfony HttpClient Component?
body: <p>I'm using Symfony HttpClient Component, it became necessary to use it with a proxy. Open proxy with the port, I can easily configure with the default configuration when instantiating CurlHttpClient class, but I can't set username and password for private proxy</p>
  
  <p>Example of default configuration:</p>
  
  <pre class="lang-php prettyprint-override"><code>use Symfony\Component\HttpClient\CurlHttpClient;
  
  $httpClient = new CurlHttpClient([
      'http_version' =&gt; '2.0',
      'proxy' =&gt; 'x.xx.xxx.xxx:8000',
  ]);
  </code></pre>
  
  <p>I try to add additional configuration on the extra options, and try other combinations, but can't find the right way.</p>
  
  <p>with plain PHP and cURL everything works fine.</p>
  
  <p>Please, help me, configure the Symfony HttpClient Component with a private proxy.</p>