title: From VS2013 to VS2017 std::async does not start a new thread
body: <p>I updated my Visual Studio from 2013 to 2017. 
  Compiling was fine but it seems like that the std::async call didn't open a new thread. (I cant see a new one in the thread-window while debugging. Also it looks like the thread which calls the the async function does the job...)</p>
  
  <p>That is my function call:</p>
  
  <pre><code>std::async(std::launch::async, myfunction, this); 
  </code></pre>
  
  <p>I didn't change anything in my code and in VS2013 was everything working fine.</p>
  
  <p>Any Idea? Google can't tell me a lot about this but maybe i have the wrong keywords. So keywords would also help!</p>
  
  <p>Thank you</p>