span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">beast</span><span class="special">::</span><span class="identifier">websocket</span><span class="special">::</span><span class="identifier">is_upgrade</span><span class="special">(</span><span class="identifier">req</span><span class="special">))</span>
    <span class="special">{</span>
        <span class="identifier">boost</span><span class="special">::</span><span class="identifier">beast</span><span class=