code: public static EventLoopGroup newEventLoopGroup(int numThreads, ThreadFactory threadFactory) {
  
          checkArgument(numThreads > 0, "numThreads: %s (expected: > 0)", numThreads);
          requireNonNull(threadFactory, "threadFactory");
  
          final TransportType type = TransportType.detectTransportType();
          return type.newEventLoopGroup(numThreads, unused -> threadFactory);
      }
docs: Returns a newly-created {@link EventLoopGroup}.
  
  @param numThreads the number of event loop threads
  @param threadFactory the factory of event loop threads