title: SortedSet<T> vs HashSet<T>
body: <p>My question is that what is the need of <code>HashSet&lt;T&gt;</code> when we have <code>SortedSet&lt;T&gt;</code>! All HashSet's methods are available in SortedSet too, moreover SortedSet is advantageous as it provides collection already in sorted manner! Even then HashSet is present. For what is it useful then?</p>