title: Enumerable OrderBy - are null values always treated high or low and can this be considered stable behaviour?
body: <p>I am sorting some <code>IEnumerable</code> of objects:</p>
  
  <pre><code>var sortedObjects = objects.OrderBy(obj =&gt; obj.Member)
  </code></pre>
  
  <p>Where Member is of an <code>IComparable</code> type. This sort seems to put objects with <code>obj.Member == null</code> at the top. This is roughly the behaviour that I want, but can I consider this to be stable with respect to future .NET frameworks? Is there a way I can make this 'nulls are low' behaviour more explicit?</p>