title: Thread safe when using Task.WhenAll
body: <pre><code>public async Task&lt;Informations&gt; DoSthAsync
  {
     var informations = new List&lt;Informations&gt;();
     await Task.WhenAll(FirstTask(informations), SecondTask(informations));
  
     return informations;
  }
  
  public async Task FirstTask(List&lt;Informations&gt; list)
  {
     await Task.Run( () =&gt; //do sth with list);
  }
  
  public async Task SecondTask(List&lt;Informations&gt; list)
  { 
    await Task.Run( () =&gt; //do sth with list);
  }
  </code></pre>
  
  <p>I would like to ask, if this code may cause problems, when two task would be using same list?</p>
  
  <p>Thank you.</p>