docs: public void gracefullyShutdownClientChannels()
      {
          LOG.warn("Gracefully shutting down all client channels");
          try {
              List<ChannelFuture> futures = new ArrayList<>();
              channels.forEach(channel -> {
                  ConnectionCloseType.setForChannel(channel, ConnectionCloseType.DELAYED_GRACEFUL);
                  ChannelFuture f = channel.pipeline().close();
                  futures.add(f);
              });
  
              LOG.warn("Waiting for " + futures.size() + " client channels to be closed.");
              for (ChannelFuture f : futures) {
                  f.await();
              }
              LOG.warn(futures.size() + " client channels closed.");
          }
          catch (InterruptedException ie) {
              LOG.warn("Interrupted while shutting down client channels");
          }
      }