public function add($key, $value)
    {
        $storageKey = $this->computeStorageKey($key);
        $this->storage[$storageKey] = array($key, $value);
        $this->counter++;
    }
public function add($key, $value)
    {
        $storageKey = $this->computeStorageKey($key);
        $this->storage[$storageKey] = array($key, $value);
        $this->counter++;
    }
{@inheritDoc}