/span> <span class="keyword">int</span> <span class="special">&gt;()),</span>  <a class="co" name="log.detailed.sink_frontends.async.c16" href="sink_frontends.html#log.detailed.sink_frontends.async.c17"><img src="../../../../../../doc/src/images/callouts/6.png" alt="6" border="0"></a>
        <span class="identifier">keywords</span><span class="special">::</span><span class="identifier">ordering_window</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span>