title: Async WCF call with ChannelFactory and CreateChannel
body: <p>I work on project where web application hosted on web server calls WCF services hosted on the app server. Proxy for WCF calls is created by ChannelFactory and calls are made via channel, example:</p>
  
  <p>(omitting using block)</p>
  
  <pre><code>var factory = new ChannelFactory&lt;IUserService&gt;(endpointConfigurationName);
  var channel = factory.CreateChannel();
  
  var users = channel.GetAllUsers();
  </code></pre>
  
  <p>If I understand it well call via channel is async and thread on the web server is idle during request and just wait for a response.</p>
  
  <p>I would like to make call async like this:</p>
  
  <pre><code>var users = await channel.GetAllUsersAsync();
  </code></pre>
  
  <p>Is there a way how to make call with ChannelFactory and channels async? I didn't find any. I know that I can generate async methods via svcutil / Add service reference but I do not want to do that. Also I don't want to change interface of service on app server (IUserService) by adding async methods.</p>
  
  <p>Is there any way how to call methods async with ChannelFactory? Thanks.</p>