</span><span class="special">.</span><span class="identifier">control_callback</span><span class="special">(</span>
    <span class="special">[](</span><span class="identifier">frame_type</span> <span class="identifier">kind</span><span class="special">,</span> <span class="identifier">string_view</span> <span class="identifier">payload</span><span class="special">)</span>
    <span class="special">{</span>
        <span class="comment">// Do something with the payload</span>
        <span class="identifier