title: socket io getting peer client certificate always returns empty object
body: <p>I need to check every peer client certificate through sockets, so I am using socket.io with NodeJS and here's what I did in the server to fetch the certificate:</p>
  
  <p><strong>Server Side</strong></p>
  
  <pre><code>io.on('connection', function(socket) {
    let cert = socket.client.request.client.getPeerCertificate();
  });
  </code></pre>
  
  <p><strong>Client Side</strong></p>
  
  <pre><code>  const io = require('socket.io-client'),
    ioClient = io.connect(
      'https://myawesomesockets.com',
      {
        secure: true
      }
    );
  </code></pre>
  
  <p>So the cert object is empty whenever I am trying to connect in the client. Is there something I am missing ? Thanks in advance !</p>