is definition">¶</a><br /></dt>
<dd><p>This method is called each time the device receives a MQTT message. It can be any MQTT message so the method should always verify the topic.</p>
<dl class="field-list simple">
<dt class="field-odd">Parameters</dt>
<dd class="field-odd"><ul class="simple">
<li><p><strong>topic</strong> – The topic on which the message was produced. </p></li>
<li><p><strong>payload</strong> – The payload of the message. It can be nullptr. </p></li>
<li><p><strong>length</strong> –