code: public ItemRef presence(final OnPresence onPresence, final OnError onError) {
  		context.presence(channel, onPresence, onError);
  		return this;
  	}
docs: Retrieves the number of the table subscriptions and their respective connection metadata (limited to the first 100 subscriptions). Each subscriber is notified of changes made to the table.
  
  @param onPresence
  Response from the server when the request was completed successfully.
  @param onError
  Response if client side validation failed or if an error was returned from the server.
  @return