  <span class="keyword">auto</span> <span class="identifier">body_cb</span> <span class="special">=</span>
    <span class="special">[&amp;](</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">uint64_t</span> <span class="identifier">remain</span><span class="special">,</span>   <span class="comment">// The number of bytes left in this chunk</span>
        <span class="identifier">string_view</span> <span class="identifier">body</span><span class="special">,</sp