pan class="identifier">Flush</span><span class="special">::</span><span class="identifier">none</span></code>, <code class="computeroutput"><span class="identifier">Flush</span><span class="special">::</span><span class="identifier">sync</span></code>,
          <code class="computeroutput"><span class="identifier">Flush</span><span class="special">::</span><span class="identifier">finish</span></code>, <code class="computeroutput"><span class="identifier">Flush</span><span class="special">::</span><span cl