title: Execution sequence when two NSNotifications are posted
body: <p>A quick question about <code>NSNotification</code>... If I post two <code>NSNotifications</code> in a method, and they are observed by different objects, what is the sequence of execution of the selector method?</p>
  
  <p>For instance, if I have three controllers - Poster, Receiver A and Receiver B. In a function of the Poster controller, I do the following:</p>
  
  <pre><code>[[NSNotificationCenter defaultCenter] postNotificationName:@"ReceiverADoSomething" object:self];
  [[NSNotificationCenter defaultCenter] postNotificationName:@"ReceiverBDoSomething" object:self];
  </code></pre>
  
  <p>In the viewDidLoad method for receiver A:</p>
  
  <pre><code>[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(workToDoByA:) name:@"ReceiverADoSomething" object:nil];
  </code></pre>
  
  <p>In the viewDidLoad method for receiver B:</p>
  
  <pre><code>[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(workToDoByB:) name:@"ReceiverADoSomething" object:nil];
  </code></pre>
  
  <p>Will <code>workToDoByA</code> be done first followed by <code>workToDoByB</code>?
  Or they will be executed together?</p>
  
  <p>Another scenario... If I have Poster A posting a notification but there are two observers to the SAME notification. What is the execution sequence then?</p>
  
  <p>Thanks in advance for your help.</p>