private static ImmutableMap<String, String> getLabels(final List<String> labelKeys, final Sample sample) {
            return labelKeys.stream()
                            .collect(toImmutableMap(
                                Function.identity(),
                                labelKey -> sample.labels.getOrDefault(labelKey, "")
                            ));
        }
The parsing context holds key results more than sample collection.
oap-server/analyzer/meter-analyzer/src/main/java/org/apache/skywalking/oap/meter/analyzer/dsl/SampleFamily.java