code: private void performNotificationImp(boolean performUpdate) {
          // Getting pending notifications list
          List<PendingNotification> destNotifications = getNotifications();
          if (destNotifications.size() == 0) {
              hideNotification();
              return;
          }
  
          // Converting to PendingNotifications
          List<Notification> res = new ArrayList<>();
          for (PendingNotification p : destNotifications) {
              boolean isChannel = false;
              if (p.getPeer().getPeerType() == PeerType.GROUP) {
                  isChannel = groups().getValue(p.getPeer().getPeerId()).getGroupType() == GroupType.CHANNEL;
              }
              res.add(new Notification(p.getPeer(), isChannel, p.getSender(), p.getContent()));
          }
  
          // Performing notifications
          if (performUpdate) {
              config().getNotificationProvider().onUpdateNotification(context().getMessenger(), res,
                      pendingStorage.getMessagesCount(), pendingStorage.getDialogsCount());
          } else {
              config().getNotificationProvider().onNotification(context().getMessenger(), res,
                      pendingStorage.getMessagesCount(), pendingStorage.getDialogsCount());
          }
      }
docs: Method for showing/updating notifications
  
  @param performUpdate is need to perform update instead of showing