@Override
    public boolean keyExists(String spaceId, String key) throws IOException {
        /*
         * Call get(spaceId, key)!=null or delegate to kdStorage.keyExists(spaceId, key)?
         * Since DELETE and PUT operations can be async, delegating to kdStorage.keyExists(spaceId,
         * key) would be preferred to avoid out-of-date data.
         */
        return kdStorage.keyExists(spaceId, key);
    }
@ Override public boolean keyExists ( String spaceId , String key ) throws IOException { return kdStorage . keyExists ( spaceId , key ) ; }
{@inheritDoc}