如何在发送下一个内容之前等待变量的更改，websocket by reactor-netty

import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import reactor.core.publisher.Flux;
import reactor.netty.http.client.WebsocketClient;

public class WebsocketExample {
    public static void main(String[] args) {
        WebsocketClient.create()
                .uri("ws://localhost:8080/ws")
                .handle((inbound, outbound) -> {
                    Flux<String> messages = Flux.just("message1", "message2", "message3");
                    return outbound.sendString(messages.map(TextWebSocketFrame::new))
                            .then()
                            .thenMany(inbound.receive().asString())
                            .doOnNext(message -> {
                                // 在这里检查变量的状态，并等待变量的更改
                                if (isVariableChanged()) {
                                    // 变量已更改，执行下一步操作
                                    System.out.println("Variable changed: " + message);
                                    // 发送下一个内容
                                    outbound.sendString(Flux.just("next message").map(TextWebSocketFrame::new));
                                } else {
                                    // 变量未更改，继续等待
                                    System.out.println("Waiting for variable change...");
                                }
                            })
                            .then();
                })
                .connect()
                .block()
                .onDispose()
                .block();
    }

    private static boolean isVariableChanged() {
        // 检查变量的状态，并返回是否变更的结果
        // 这里省略具体实现
        return false;
    }
}