带有hystrix回退的spring-cloud-gateway，如何获取异常详细信息？

import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.core.Ordered;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

@Component
public class ExceptionDetailFilter implements GatewayFilter, Ordered {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        return chain.filter(exchange)
                .onErrorResume(throwable -> {
                    if (throwable instanceof Exception) {
                        // 获取异常详细信息
                        String errorMessage = throwable.getMessage();
                        // 处理异常详细信息，例如记录日志或返回给客户端
                        // ...
                    }
                    // 返回一个自定义的响应
                    ServerHttpRequest request = exchange.getRequest().mutate()
                            .header("X-Exception-Message", throwable.getMessage())
                            .build();
                    exchange.getResponse().setStatusCode(HttpStatus.INTERNAL_SERVER_ERROR);
                    return chain.filter(exchange.mutate().request(request).build());
                });
    }

    @Override
    public int getOrder() {
        // 设置过滤器的执行顺序，可以根据实际情况调整
        return Ordered.HIGHEST_PRECEDENCE;
    }
}

import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class GatewayConfig {

    @Bean
    public GlobalFilter exceptionDetailFilter() {
        return new ExceptionDetailFilter();
    }
}