fies this section.</p>

<p>Typically you want to base this diffing key on data that is stored in the model.
For example:</p>
<pre class="highlight swift"><code> <span class="kd">public</span> <span class="k">var</span> <span class="nv">diffingKey</span> <span class="o">=</span> <span class="p">{</span> <span class="n">group</span><span class="o">.</span><span class="n">identifier</span> <span class="p">}</span>
</code></pre>

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