title: Replacing an element in ICollection
body: <p>Suppose I have an <code>ICollection&lt;SomeClass&gt;</code>.</p>
  
  <p>I have the following two variables:</p>
  
  <pre><code>SomeClass old;
  SomeClass new;
  </code></pre>
  
  <p>How can I achieve something like the following using an <code>ICollection&lt;SomeClass&gt;</code>?</p>
  
  <pre><code>// old is guaranteed to be inside collection
  collection.Replace(old, new);
  </code></pre>