src/Uploadcare/PagedDataIterator.php
private function exists($offset = null)
    {
        return isset($this->container[$offset !== null ? $offset : $this->position]);
    }
private function exists($offset = null)
    {
        return isset($this->container[$offset !== null ? $offset : $this->position]);
    }
Check if element exists. Uses current position if no offset provided

@param int $offset
@return bool