title: How can I efficiently determine if an IEnumerable has more than one element?
body: <p>Given an initialised <code>IEnumerable</code>:</p>
  
  <pre><code>IEnumerable&lt;T&gt; enumerable;
  </code></pre>
  
  <p>I would like to determine if it has more than one element. I think the most obvious way to do this is:</p>
  
  <pre><code>enumerable.Count() &gt; 1
  </code></pre>
  
  <p>However, I believe <code>Count()</code> enumerates the <em>whole</em> collection, which is unnecessary for this use case. For example, if the collection contains a very large amount of elements or provided its data from an external source, this could be quite wasteful in terms of performance.</p>
  
  <p>How can I do this without enumerating any more than 2 elements?</p>