title: HttpClient.GetAsync with network credentials
body: <p>I'm currently using <code>HttpWebRequest</code> to get a website. I'd like to use the await pattern, which is not given for <code>HttpWebRequests</code>. I found the class <code>HttpClient</code>, which seems to be the new Http worker class. I'm using <code>HttpClient.GetAsync(...)</code> to query my webpage. But I'm missing the option to add <code>ClientCredentials</code> like <code>HttpWebRequest.Credentials</code>. Is there any way to give the <code>HttpClient</code> authentication information?</p>