AddRequestFormatsListener

Adds request formats.

Returns an array of event names this subscriber wants to listen to.

The array keys are event names and the value can be:

• The method name to call (priority defaults to 0)
• An array composed of the method name to call and the priority
• An array of arrays composed of the method names to call and respective priorities, or 0 if unset

For instance:

• array('eventName' => 'methodName')
• array('eventName' => array('methodName', $priority))
• array('eventName' => array(array('methodName1', $priority), array('methodName2'))