public static void addHttpStatus(Builder<Tag> tagListBuilder, RequestLog log) {
        requireNonNull(tagListBuilder, "tagListBuilder");
        requireNonNull(log, "log");
        // Add the 'httpStatus' tag.
        final HttpStatus status;
        if (log.isAvailable(RequestLogProperty.RESPONSE_HEADERS)) {
            status = log.responseHeaders().status();
        } else {
            status = HttpStatus.UNKNOWN;
        }
        tagListBuilder.add(Tag.of("http.status", status.codeAsText()));
    }
Adds {@code http.status} tag to the {@code tagListBuilder}.
core/src/main/java/com/linecorp/armeria/internal/common/metric/DefaultMeterIdPrefixFunction.java