title: Pusher send presence event to specific member
body: <p>Is it possible to specify the member id of an event so that <strong>only</strong> that member would receive the event?</p>
  
  <p>If for instance I want to send a notification to a user (who's user ID I know) how would I do that? I'm storing the member/user ID in the presence authentication - </p>
  
  <p><code>$pusher-&gt;presence_auth($_POST['channel_name'], $_POST['socket_id'], $user_id)
  , $user_data);</code> </p>
  
  <p>I want to be able to trigger an event for a specific user_id</p>
  
  <pre><code>$pusher-&gt;trigger( 'presence-test', 'test_event', $data, $socket_id );
  </code></pre>
  
  <p>Is it possible?</p>
  
  <p>Any advice appreciated, thanks!</p>