private String getTraceId() {
        return (String) exchange.getAttributes().get(GenericLoggingConstant.SHENYU_AGENT_TRACE_ID);
    }
Encourage developers to provide plugins to upstream like SkyWalking, ZipKin and OpenTelemetry
to implement the tracing features. These plug-ins can set a traceId to the context.

@return traceId
shenyu-plugin/shenyu-plugin-logging/shenyu-plugin-logging-common/src/main/java/org/apache/shenyu/plugin/logging/common/body/LoggingServerHttpResponse.java