如何衡量webflux WebClient方法的执行时间？

import org.springframework.web.reactive.function.client.WebClient;
import reactor.core.publisher.Mono;

public class WebClientExample {
    public static void main(String[] args) {
        // 创建WebClient实例
        WebClient webClient = WebClient.create();

        // 创建起始时间点的计时器
        long startTime = System.currentTimeMillis();

        // 发起WebClient请求
        Mono<String> response = webClient.get()
                .uri("https://example.com/api")
                .retrieve()
                .bodyToMono(String.class);

        // 等待响应结果
        String result = response.block();

        // 计算执行时间
        long executionTime = System.currentTimeMillis() - startTime;

        // 输出执行时间
        System.out.println("WebClient方法执行时间：" + executionTime + "毫秒");
    }
}