private static void addGrpcStatus(ImmutableList.Builder<Tag> tagListBuilder, RequestLog log) {
        String status = log.responseHeaders().get(GrpcHeaderNames.GRPC_STATUS);
        if (status != null) {
            tagListBuilder.add(statusTag(status));
            return;
        }

        status = log.responseTrailers().get(GrpcHeaderNames.GRPC_STATUS);
        if (status != null) {
            tagListBuilder.add(statusTag(status));
            return;
        }

        final HttpHeaders trailers = GrpcWebTrailers.get(log.context());
        if (trailers != null) {
            status = trailers.get(GrpcHeaderNames.GRPC_STATUS);
            if (status != null) {
                tagListBuilder.add(statusTag(status));
                return;
            }
        }

        tagListBuilder.add(UNKNOWN_TAG);
    }
Returns a newly created {@link GrpcMeterIdPrefixFunction} with the specified {@code name}.
grpc/src/main/java/com/linecorp/armeria/common/grpc/GrpcMeterIdPrefixFunction.java