title: start all dialogs (chat room) to autodownload attachments in quickblox
body: <p>What i want to implement is auto-download attachment functionality without entering in ChatRoom, using QuickBlox SDK iOS version 2.0.12,</p>
  
  <p>To do that all i want to start all the dialogs (chat rooms) that user belongs after login.</p>
  
  <p>With current api what user can see the list of Dialogs (chat rooms) and enter in only one room at a time. 
  So, suppose there are 2 chat rooms (ChatRoom A,ChatRoom B) for the logged in user, so when he enters 'ChatRoom A', he can only receive messages/attachments for 'ChatRoom A' as Notification in chatDidReceiveMessageNotification / chatRoomDidReceiveMessageNotification. </p>
  
  <p>So when user receives a message/attachment for 'ChatRoom B' he will not be able to access until he enters the 'ChatRoom B'.</p>
  
  <p>To have it worked, i created following method in DialogsViewController :
  which is trying to join all the dialogs(chat rooms) </p>
  
  <pre><code>-(void)startallrooms
  {
      [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(chatDidReceiveMessageNotification:)
                                                       name:kNotificationDidReceiveNewMessage object:nil];
      [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(chatRoomDidReceiveMessageNotification:)
                                                       name:kNotificationDidReceiveNewMessageFromRoom object:nil];
      QBChatRoom *chatRooms;
  
      for (int i=0; i&lt;=self.dialogs.count; i++) {
          QBChatDialog *dialog = self.dialogs[i];
          chatRooms = [dialog chatRoom];
          [[ChatService instance] joinRoom:chatRooms completionBlock:^(QBChatRoom *joinedChatRoom) {
                  // joined
          }];
      }   
  }
  </code></pre>
  
  <p>And called from completedWithResult from DialogsViewController.</p>
  
  <pre><code>- (void)completedWithResult:(Result *)result{
      if (result.success &amp;&amp; [result isKindOfClass:[QBDialogsPagedResult class]]) {
          [self startallrooms];
          ..
          ..
       }
  }
  </code></pre>
  
  <p>It is giving an error : EXC_BAD_ACCESS in following method from ChatService.m</p>
  
  <pre><code>- (void)chatRoomDidEnter:(QBChatRoom *)room{
  }
  </code></pre>
  
  <p>But when i try to join only one ChatRoom, it doesn't give me any error and works perfectly fine.
  (just check replacing <strong>for loop</strong> with this -> for (int i=0; i&lt;=0; i++) in <strong>startallrooms</strong> method that i mentioned above)</p>
  
  <p>So, where am i going wrong and even if i solve this issue, is it feasible from memory perspective to start all the rooms (if user is having thousands of rooms) ? After implementing same i will be doing it on Android also.</p>