private static String measurementName(Meter.Id id, Measurement measurement) {
        final StringBuilder buf = new StringBuilder();

        // Append name.
        buf.append(id.getName());

        // Append statistic.
        buf.append('#');
        buf.append(measurement.getStatistic().getTagValueRepresentation());

        // Append tags if there are any.
        final Iterator<Tag> tagsIterator = id.getTags().iterator();
        if (tagsIterator.hasNext()) {
            buf.append('{');
            tagsIterator.forEachRemaining(tag -> buf.append(tag.getKey()).append('=')
                                                    .append(tag.getValue()).append(','));
            buf.setCharAt(buf.length() - 1, '}');
        }
        return buf.toString();
    }
Returns a newly-created immutable {@link Map} which contains all values of {@link Meter}s in the
specified {@link MeterRegistry}. The format of the key string is:
<ul>
  <li>{@code <name>#<statistic>{tagName=tagValue,...}}</li>
  <li>e.g. {@code "armeria.server.active.requests#value{method=greet}"}</li>
  <li>e.g. {@code "some.subsystem.some.value#count"} (no tags)</li>
</ul>
Note: It is not recommended to use this method for the purposes other than testing.
core/src/main/java/com/linecorp/armeria/common/metric/MoreMeters.java