title: Metro StorageFile Multithreaded File logging
body: <p>What is the correct way for handling multithreaded file access to the <code>StorageFile</code> object?</p>
  
  <p>After creating a <code>StorageFile</code>, I write to it using <code>FileIO.AppendTextAsync</code>.</p>
  
  <p>This works, but as soon as multiple threads call <code>FileIO.AppendTextAsync</code>, I get Access Denied errors - presumably because a previous call to it, is still running.</p>
  
  <p>How do I deal with this situation?</p>