ransactions to allow external libraries or user apps to store their own custom data.</p>
<pre class="highlight swift"><code><span class="kd">enum</span> <span class="kt">Static</span> <span class="p">{</span>
    <span class="kd">static</span> <span class="k">var</span> <span class="nv">myDataKey</span><span class="p">:</span> <span class="kt">Void</span><span class="p">?</span>
<span class="p">}</span>
<span class="kt">CoreStoreDefaults</span><span class="o">.</span><span class="n">dataStack</span><span cl