title: What is the difference between HashSet<T> and List<T>?
body: <p>Can you explain what is the difference between <code>HashSet&lt;T&gt;</code> and <code>List&lt;T&gt;</code> in .NET? </p>
  
  <p>Maybe you can explain with an example in what cases <code>HashSet&lt;T&gt;</code> should be preferred against <code>List&lt;T&gt;</code> ?</p>