docs: public boolean addConsumer( final C consumer,
                                  final int timesToRetryUponTimeout ) {
          if (!addEntries.get()) {
              throw new IllegalStateException();
          }
          ConsumerRunner runner = new ConsumerRunner(consumer, timesToRetryUponTimeout);
          if (gcConsumer != null) gcConsumer.stayBehind(runner.getPointer());
  
          // Try to add the runner instance, with equality based upon consumer instance equality ...
          if (!consumers.add(runner)) return false;
  
          // It was added, so start it ...
          executor.execute(runner);
          return true;
      }