title: Attempting to Modify Object Outside of Write Transaction
body: <p>So I have no idea why I am getting this error. The error message is as follows:</p>
  
  <p><strong>* Terminating app due to uncaught exception 'RLMException', reason: 'Attempting to modify object outside of a write transaction - call beginWriteTransaction on a RLMRealm instance first.'
  *</strong> First throw call stack:
  (0x2f7b0f83 0x39f61ccf 0xc46ef 0xc3c23 0xc0c9d 0xb3e73 0x3a449833 0x3a449ded 0x3a44a297 0x3a45c88d 0x3a45cb21 0x3a58bbd3 0x3a58ba98)
  libc++abi.dylib: terminating with uncaught exception of type NSException</p>
  
  <p>And is thrown while executing this code.</p>
  
  <pre><code>- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
  {
      UITextField * alertTextField = [alertView textFieldAtIndex:0];
      if (![self.chatSession.theirAlias isEqualToString:alertTextField.text]) {
          self.sender = alertTextField.text;
          dispatch_queue_t queue = ((AppDelegate *)[UIApplication sharedApplication].delegate).queueForWrites;
          dispatch_async(queue, ^{
              [[RLMRealm defaultRealm] beginWriteTransaction];
              self.chatSession.myAlias = alertTextField.text; // This is the line where the error is thrown
              [[RLMRealm defaultRealm] commitWriteTransaction];
          });
      } else {
          [self promptForAliasAfterRejection];
      }
  }
  </code></pre>
  
  <p>It's pretty clear that I am writing inside of a write transaction. Is this a bug with Realm? Or am I missing something...?</p>