impl</span><span class="special">,</span>
    <span class="keyword">const</span> <span class="identifier">time_point</span> <span class="special">&amp;</span> <span class="identifier">expiry_time</span><span class="special">,</span>
    <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span> <span class="special">&amp;</span> <span class="identifier">ec</span><span class="special">);</