title: Wait for messages processed by Service Bus OnMessage to finish
body: <p>I'm using the Azure Service Bus SubscriptionClient.OnMessage method; configured to process up to 5 messages concurrently.</p>
  
  <p>Within the code I need to wait for all messages to finish processing before I can continue (to properly shutdown an Azure Worker Role). How do I do this?</p>
  
  <p>Will SubscriptionClient.Close() block until all messages have finished processing?</p>