ocks.html#stateful-functions"><em>stateful function</em></a>, which has the following properties:</p>
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<li>
<p>It has a logical unique address; and persisted, fault tolerant state, scoped to that address.</p>
</li>
<li>
<p>It can <em>react</em> to messages, both internal (or, sent from other stateful functions) and external (e.g. a message from Kafka).</p>
</li>
<li>
<p>Invocations of a specific function are serializable, so messages sent to a specific address are <strong>not</strong> executed concurren