title: How to use async with Visual Studio 2010 and .NET 4.0?
body: <p>I want to add async support to current VS 2010 .NET 4.0 C# project</p>
  
  <p>I have found:</p>
  
  <ul>
  <li>Visual Studio Async CTP - <a href="http://www.microsoft.com/en-us/download/details.aspx?id=9983" rel="noreferrer">http://www.microsoft.com/en-us/download/details.aspx?id=9983</a></li>
  <li>Microsoft.Bcl.Async - <a href="https://nuget.org/packages/Microsoft.Bcl.Async" rel="noreferrer">https://nuget.org/packages/Microsoft.Bcl.Async</a></li>
  </ul>
  
  <p>I don't even get real difference between them.</p>
  
  <p>I installed both. Visual Studio Async CTP (Version 3), Microsoft.Bcl and Microsoft.Bcl.Async. (also used to run <code>tools\portable-net40+sl4+win8+wp71\install.ps1</code> in Microsoft.Bcl)</p>
  
  <p>And still  can't see any effect. Same error for</p>
  
  <pre><code>public async Task&lt;CommResponse&gt;
  </code></pre>
  
  <p>-></p>
  
  <pre><code>Error   37  The type or namespace name 'async' could not be found (are you missing a using directive or an assembly reference?)
  </code></pre>
  
  <p>So is it real how should I use this stuff?</p>