public SampleFamilyBuilder defaultHistogramBucketUnit(TimeUnit unit) {
        this.context.setDefaultHistogramBucketUnit(unit);
        return this;
    }
Help to build the {@link SampleFamily}.
oap-server/analyzer/meter-analyzer/src/main/java/org/apache/skywalking/oap/meter/analyzer/dsl/SampleFamilyBuilder.java