title: Callback in renderer function for ExtJS Grid
body: <p>I've got a renderer function that has to load some data from a store in order to return a value, but I haven't been able to figure out how to return what I want to the grid column.</p>
  
  <pre><code>{header: 'Manager First Name', 
  renderer: function(value, meta, record){
      record.Managers().load({
          scope: this,
          callback: function(managers, operation, success){
              if(success &amp;&amp; managers){
                 managers[0].getPerson({
                      scope: this,
                      callback: function(person, operation){
                          if(person){
                              return person.get("firstName");
                          } else {
                              console.error('This manager doesn\'t have a person record.');
                              return '';
                          }
                      }
                  });
              } else {
                  console.error('No manager record for the shop '+record.getId());
              }
          }
      });
  }}
  </code></pre>
  
  <p>I've tried placing <code>return</code> in front of the <code>load</code> and the <code>getPerson</code> functions to no avail. I thought of firing an event as well, but I'm not sure how that would look. Any ideas?</p>