al">::</span><span class="identifier">uint64_t</span> <span class="identifier">size</span><span class="special">,</span>         <span class="comment">// Size of the chunk, zero for the last chunk</span>
    <span class="identifier">string_view</span> <span class="identifier">extensions</span><span class="special">,</span>     <span class="comment">// The chunk-extensions in raw form</span>
    <span class="identifier">error_code</span><span class="special">&amp;</span> <span class="identifier">ec</span><sp