无法在webflux中以反应式方式返回请求

import org.springframework.http.MediaType;
import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.ServerResponse;
import org.springframework.web.reactive.function.server.RouterFunctions;
import org.springframework.web.reactive.function.server.ServerRequest;
import reactor.core.publisher.Mono;

public class ReactiveHandler {

    public Mono<ServerResponse> handleRequest(ServerRequest request) {
        // 处理请求逻辑
        Mono<String> responseMono = Mono.just("Hello, World!");

        return ServerResponse.ok()
                .contentType(MediaType.TEXT_PLAIN)
                .body(responseMono, String.class);
    }

    public RouterFunction<ServerResponse> route() {
        return RouterFunctions.route()
                .GET("/api/hello", this::handleRequest)
                .build();
    }
}

public class Application {

    public static void main(String[] args) {
        ReactiveHandler handler = new ReactiveHandler();

        RouterFunction<ServerResponse> router = handler.route();

        // 使用Netty服务器启动WebFlux应用
        HttpServer httpServer = HttpServer.create().port(8080);
        ReactorHttpHandlerAdapter handlerAdapter = new ReactorHttpHandlerAdapter(RouterFunctions.toHttpHandler(router));
        httpServer.handle(handlerAdapter).bindNow();
    }
}