code: private static Class<? extends Channel> epollChannelType() {
      try {
        Class<? extends Channel> channelType = Class
            .forName("io.netty.channel.epoll.EpollSocketChannel").asSubclass(Channel.class);
        return channelType;
      } catch (ClassNotFoundException e) {
        throw new RuntimeException("Cannot load EpollSocketChannel", e);
      }
    }
docs: Must call when epoll is available