public function removeItem(string $key): bool
    {
        if (!$this->adapter instanceof iAdapter) {
            return false;
        }

        $storeKey = $this->calculateStoreKey($key);

        // remove static-cache
        if (
            !empty(self::$STATIC_CACHE)
            &&
            \array_key_exists($storeKey, self::$STATIC_CACHE)
        ) {
            unset(
                self::$STATIC_CACHE[$storeKey],
                self::$STATIC_CACHE_COUNTER[$storeKey],
                self::$STATIC_CACHE_EXPIRE[$storeKey]
            );
        }

        return $this->adapter->remove($storeKey);
    }