              </td>
<td>
                <p>
                  This policy keeps around a buffer id, or a buffer age. Every time
                  <code class="computeroutput"><span class="identifier">clear_queue</span><span class="special">()</span></code>
                  is called on a <code class="computeroutput"><span class="identifier">multi_pass</span></code>
                  iterator, it is possible that all other iterators become invalid.
                  When <code class="computeroutput"><span 