Fastest way to compare two List<CustomObject>
<p>I have two <code>List&lt;CustomObject&gt;</code>, called list1 and list2</p>

<pre><code>public class CustomObject
{
    public string foo { get; set; }
    public string bar{ get; set; }
}
</code></pre>

<p>The goal is to generate a new list with all the entries that have been modified/added in list2.</p>

<p>Because these lists can get pretty long, looping through them is not an option ...</p>

<p>Any ideas?</p>