code: protected void activateConsumers(List<ConsumerHolder> consumerHolders) throws IOException {
          synchronized (activationMonitor) {
              for (ConsumerHolder consumerHolder : consumerHolders) {
                  try {
                      consumerHolder.activate();
                  } catch (IOException e) {
                      LOGGER.error("Failed to activate consumer - deactivating already activated consumers");
                      deactivateConsumers(consumerHolders);
                      throw e;
                  }
              }
          }
      }
docs: Activates all consumers in the given list.
  
  @param consumerHolders The list of consumers to activate
  @throws IOException if the activation process fails for a consumer