return buckets.stream().map(e -> {
                final Map<String, Object> map = new HashMap<>();
                map.put(ID, Base64.getUrlEncoder().encodeToString(e.getKeyAsString().getBytes(StandardCharsets.UTF_8)));
                map.put(KEY, e.getKeyAsString());
                map.put(COUNT, e.getDocCount());
                return map;
            }).collect(Collectors.toList());