title: ebay-sdk-php notification handling
body: <p>I'm using the <a href="https://github.com/davidtsadler/ebay-sdk-php" rel="nofollow noreferrer">https://github.com/davidtsadler/ebay-sdk-php</a>, the unofficial PHP SDK for eBay.</p>
  
  <p>I've been going around in circles with notifications, particularly 'FixedPriceTransaction' notifications. I've managed to subscribe to the notifications and send a request to ensure that the subscription has been correctly created.</p>
  
  <p>Unfortunately I can't work out which method to use when the notification is sent by eBay to handle it.</p>