将循环阻塞代码重写为SwiftNIO风格的非阻塞代码

let eventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: System.coreCount)
defer { try? eventLoopGroup.syncShutdownGracefully() }

let bootstrap = ServerBootstrap(group: eventLoopGroup)
    .childChannelInitializer { channel in
        channel.pipeline.addHandler(YourChannelHandler())
    }
    .childChannelOption(ChannelOptions.socketOption(.so_reuseaddr), value: 1)

class YourChannelHandler: ChannelInboundHandler {
    typealias InboundIn = ByteBuffer
    typealias OutboundOut = ByteBuffer

    func channelRead(context: ChannelHandlerContext, data: NIOAny) {
        let byteBuffer = self.unwrapInboundIn(data)

        // 处理请求数据

        let responseBuffer = // 构造响应数据

        let response = self.wrapOutboundOut(responseBuffer)
        context.writeAndFlush(self.wrapOutboundOut(response), promise: nil)
    }
}

let address = try SocketAddress(ipAddress: "127.0.0.1", port: 8080)
let channel = try bootstrap.bind(to: address).wait()
try channel.closeFuture.wait()