title: Run method on main thread from another thread
body: <p>My model class has to get some data from the internet. So I decided to run it on another thread so the ui doesn't freeze.
  So when an object wants some data it first asks the model using a method of this type:</p>
  
  <pre><code>- (void)giveMeSomeData:(id)object withLabel:(id)label {
  objectAsking= object;
  theLabel= label;
  NSThread* thread= [[NSThread alloc] initWithTarget:self selector:@selector(getTheDataFromInternet) object:nil];
  [thread start];
  }
  
  - (void)getTheDataFromInternet {
  //getting data...
  
  theData= [dataFromInternet retain]; //this is the data the object asked for
  [self returnObjectToAsker];
  }
  
  - (void)returnObjectToAsker {
  [objectAsking receiveData:theData withLabel:theLabel];
  }
  </code></pre>
  
  <p>As I'm still a newbie, can you tell me if it's a good pattern?</p>
  
  <p>Thanks!</p>