="identifier">error_code</span> <span class="identifier">ec</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">bytes_transferred</span><span class="special">)</span>
        <span class="special">{</span>
            <span class="keyword">if</span><span class="special">(</span><span class="identifier">ec</span><span class="special">)</span>
                <span class="keyword">return</span><s