title: OutOfMemoryException when adding more items to a very large HashSet<Int32>
body: <p>Exception of type <code>System.OutOfMemoryException</code> was thrown while trying to add <code>23997908th</code> item in a <code>HashSet&lt;Int32&gt;</code>.</p>
  
  <p>We need maintain a high performance unique collection of integer sizeof <code>Int32</code>.MaxValue i.e. <code>2147483647</code>. <code>HashSet</code> of <code>Int32</code> can store only <code>23997907</code> items in it. Looking for a suggestion to resolve this issue.</p>