public static void gaugeDecrement(final String name, final String[] labelValues) {
        Optional.ofNullable(metricsRegister).ifPresent(register -> register.gaugeDecrement(name, labelValues));
    }
Gauge decrement.

@param name name
@param labelValues label values
shenyu-plugin/shenyu-plugin-metrics/src/main/java/org/apache/shenyu/plugin/metrics/reporter/MetricsReporter.java