tifier">boost</span><span class="special">::</span><span class="identifier">tie</span><span class="special">(</span><span class="identifier">x</span><span class="special">,</span><span class="identifier">y</span><span class="special">)=</span><span class="identifier">source</span><span class="special">.</span><span class="identifier">get</span><span class="special">();</span>
    <span class="special">});</span>

<span class="identifier">sink</span><span class="special">(</span><span class="identifier">boos