}

    /**
     * Set a given key / value pair or pairs
     *
     * @param  array<TKey, TValue>|int|string  $keys
     * @param  mixed  $value
     * @return $this
     */
    public function set($keys, $value = null)
    {
        if (is_array($keys)) {
            foreach ($keys as $key => $value) {
                $this->set($key, $value);
            }

            return $this;
        }

        $items = &$this->items;

        if (is_string($keys)) {
            foreach (explode($this->delimiter, $keys) as $key) {
                if (!isset($items[$key]) || !is_array($items[$key])) {
                    $items[$key] = [];
                }

                $items = &$items[$key];
            }
        }

        $items = $value;

        return $this;
    }

    /**
     * Replace all items with a given array
     *
     * @param  mixed  $items
     * @return $this
     */
    public function setArray($items)
    {
        $this->items = $this->getArrayItems($items);

        return $this;
    }

    /**
     * Replace all items with a given array as a reference
     *
     * @param  array<TKey, TValue>  $items
     * @return $this
     */
    public function setReference(array &$items)
    {
        $this->items = &$items;

        return $this;
    }

    /**
     * Return the value of a given key or all the values as JSON
     *
     * @param  mixed  $key
     * @param  int  $options
     * @return string|false
     */
    public function toJson($key = null, $options = 0)
    {
        if (is_string($key)) {
            return json_encode($this->get($key), $options);
        }

        $options = $key === null ? 0 : $key;

        return json_encode($this->items, $options);
    }

    /**
     * Output or return a parsable string representation of the
     * given array when exported by var_export()
     *
     * @param  array<TKey, TValue>  $items
     * @return object
     */
    public static function __set_state(array $items): object
    {
        return (object) $items;
    }

    /*
     * --------------------------------------------------------------
     * ArrayAccess interface
     * --------------------------------------------------------------
     */

    /**
     * Check if a given key exists
     *
     * @param  int|string  $key
     * @return bool
     */
    public function offsetExists($key): bool
    {
        return $this->has($key);
    }

    /**
     * Return the value of a given key
     *
     * @param  int|string  $key
     * @return mixed
     */
    #[\ReturnTypeWillChange]
    public function offsetGet($key)
    {
        return $this->get($key);
    }

    /**
     * Set a given value to the given key
     *
     * @param int|string|null  $key
     * @param mixed  $value
     */
    public function offsetSet($key, $value): void
    {
        if ($key === null) {
            $this->items[] = $value;

            return;
        }

        $this->set($key, $value);
    }

    /**
     * Delete the given key
     *
     * @param  int|string  $key
     * @return void
     */
    public function offsetUnset($key): void
    {
        $this->delete($key);
    }

    /*
     * --------------------------------------------------------------
     * Countable interface
     * --------------------------------------------------------------
     */

    /**
     * Return the number of items in a given key
     *
     * @param  int|string|null  $key
     * @return int
     */
    public function count($key = null): int
    {
        return count($this->get($key));
    }

    /*
     * --------------------------------------------------------------
     * IteratorAggregate interface
     * --------------------------------------------------------------
     */

    /**
     * Get an iterator for the stored items
     *
     * @return \ArrayIterator<TKey, TValue>
     */
    public function getIterator(): Traversable
    {
        return new ArrayIterator($this->items);
    }

    /*
     * --------------------------------------------------------------
     * JsonSerializable interface
     * --------------------------------------------------------------
     */

    /**
     * Return items for JSON serialization
     *
     * @return array<TKey, TValue>
     */
    public function jsonSerialize(): array
    {
        return $this->items;
    }
}