code: public static EventLoopGroup createEventLoop(IOMode mode, int numThreads, String threadPrefix) {
      ThreadFactory threadFactory = createThreadFactory(threadPrefix);
  
      switch (mode) {
        case NIO:
          return new NioEventLoopGroup(numThreads, threadFactory);
        case EPOLL:
          return new EpollEventLoopGroup(numThreads, threadFactory);
        default:
          throw new IllegalArgumentException("Unknown io mode: " + mode);
      }
    }
docs: Creates a Netty EventLoopGroup based on the IOMode.