@Override
    public void clear() {
        if (freezed.get()) {
            for (K k : whitelist) {
                map.remove(k);
            }
        } else {
            map.clear();
        }
    }
Checks whether the given key can be used in mutation(e.g. {@code put()},
{@code remove()}), regardless the map is freezed or not.

@param key non-null key
@return true if the given key can be used in mutation; false otherwise
clickhouse-data/src/main/java/com/clickhouse/data/ClickHouseFreezableMap.java