@Override
    public MeterIdPrefix completeRequestPrefix(MeterRegistry registry, RequestLog log) {
        /* http.method, http.status, method, path, service */
        final Builder<Tag> tagListBuilder = ImmutableList.builderWithExpectedSize(5);
        final RequestHeaders requestHeaders = log.requestHeaders();
        final String httpMethod = requestHeaders.method().name();
        tagListBuilder.add(Tag.of("http.method", httpMethod));
        addHttpStatus(tagListBuilder, log);
        addMethodPathAndService(tagListBuilder, log, requestHeaders);
        return new MeterIdPrefix(name, tagListBuilder.build());
    }
Returns a newly created {@link RetrofitMeterIdPrefixFunction} with the specified {@code name}.
retrofit2/src/main/java/com/linecorp/armeria/client/retrofit2/RetrofitMeterIdPrefixFunction.java