code: public static void presence(String url, Boolean isCluster, String applicationKey, String authenticationToken, String channel, Proxy proxy, OnPresence callback) {
  	    Presence.getPresence(url, isCluster, applicationKey, authenticationToken, channel, proxy, callback);
    }
docs: Gets the subscriptions in the specified channel and if active the first 100 unique metadata (optionally using proxy connection).
  
  <pre>
  Ortc.presence(&quot;http://ortc-developers.realtime.co/server/2.1/&quot;, true, &quot;APPLICATION_KEY&quot;, &quot;AUTHENTICATION_TOKEN&quot;,
  &quot;CHANNEL&quot;, new Proxy(&quot;my.proxy.net&quot;, 1234), new onPresence() {
  
  public void run(Exception error, Presence presence) {
  if (error != null) {
  System.out.println(error.getMessage());
  } else {
  System.out.println(&quot;Subscriptions - &quot; + presence.getSubscriptions());
  
  Iterator&lt;?&gt; metadataIterator = presence.getMetadata().entrySet().iterator();
  while (metadataIterator.hasNext()) {
  Map.Entry&lt;String, Long&gt; entry = (Map.Entry&lt;String, Long&gt;) metadataIterator.next();
  System.out.println(entry.getKey() + &quot; - &quot; + entry.getValue());
  }
  }
  }
  });
  </pre>
  
  @param url  Server containing the presence service.
  @param isCluster Specifies if url is cluster.
  @param applicationKey Application key with access to presence service.
  @param authenticationToken Authentication token with access to presence service.
  @param channel Channel with presence data active.
  @param proxy Object with definition of proxy connection (ibt.ortc.api.Proxy) or null if no proxy should be used
  @param callback Callback with error and result.