public static AttributesBuilder newAttributesBuilder() {
        AttributesBuilder attributesBuilder;
        if (attributesBuilderSupplier == null) {
            attributesBuilderSupplier = Attributes::builder;
        }
        attributesBuilder = attributesBuilderSupplier.get();
        LABEL_MAP.forEach(attributesBuilder::put);
        return attributesBuilder;
    }
@Test
    public void testNewAttributesBuilder() {
        Attributes attributes = BrokerMetricsManager.newAttributesBuilder().put("a", "b")
                .build();
        assertThat(attributes.get(AttributeKey.stringKey("a"))).isEqualTo("b");
    }