code: protected void enableConsumers(List<ConsumerHolder> consumerHolders) throws IOException {
          checkPreconditions(consumerHolders);
          try {
              for (ConsumerHolder consumerHolder : consumerHolders) {
                  consumerHolder.enable();
              }
          } catch (IOException e) {
              LOGGER.error("Failed to enable consumers - disabling already enabled consumers");
              disableConsumers(consumerHolders);
              throw e;
          }
      }
docs: Enables all consumers in the given list and hands them over for activation afterwards.
  
  @param consumerHolders The consumers to enable
  @throws IOException if the activation process fails for a consumer