    <span class="special">});</span>

<span class="keyword">while</span><span class="special">(</span><span class="identifier">source</span><span class="special">){</span>            <span class="comment">// test if pull-coroutine is valid</span>
    <span class="keyword">int</span> <span class="identifier">ret</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="comment">// ac