title: AWS Elastic Cache Cluster PHP client not working in resetServerList() function
body: <p>I have an issue with Memcached, After resetServerList() function the object is not supported to next any activities like set, add, etc...</p>
  <p>PHP version : 7.2
  AWS Elastic cache cluster client: 3.1.3</p>
  <p>After resetServerList() not working correctly</p>
  <p>The sample code is mentioned below.</p>
  <pre><code>$m = new \Memcached($persistent_id);
  $m-&gt;setOption(Memcached::OPT_LIBKETAMA_COMPATIBLE, true);
  var_dump($m-&gt;addServer($host, $port, $weight));
  echo &quot;&lt;br&gt;server List: &quot;;var_dump($m-&gt;getServerList());
  echo &quot;&lt;br&gt;Reset Server Status: &quot;;var_dump($m-&gt;resetServerList());
  echo &quot;&lt;br&gt;Add Server Status: &quot;;var_dump($m-&gt;addServer($host, $port, $weight));
  echo &quot;&lt;br&gt;Server List: &quot;;var_dump($m-&gt;getServerList());
  </code></pre>
  <p>Results:</p>
  <pre><code>Reset Server Status: bool(true)
  Add Server Status: **bool(false)**
  Server List: **array(0) { }**
  </code></pre>
  <p>Kindly any solution for this.</p>