code: @SneakyThrows
      public void start(final int port) {
          try {
              ServerBootstrap bootstrap = new ServerBootstrap();
              bossGroup = createEventLoopGroup();
              if (bossGroup instanceof EpollEventLoopGroup) {
                  groupsEpoll(bootstrap);
              } else {
                  groupsNio(bootstrap);
              }
              ChannelFuture future = bootstrap.bind(port).sync();
              future.channel().closeFuture().sync();
          } finally {
              workerGroup.shutdownGracefully();
              bossGroup.shutdownGracefully();
              BackendExecutorContext.getInstance().getExecuteEngine().close();
          }
      }
docs: Start Sharding-Proxy.
  
  @param port port