/**
* @note Despite the name, this seems to be intended to implement isset()
* rather than array_key_exists(). So do that.
+ * @inheritDoc
*/
public function offsetExists( $offset ) {
$data = &$this->backend->getData();
* data to detect such changes.
* @note Accessing a nonexistent key via this mechanism causes that key to
* be created with a null value, and does not raise a PHP warning.
+ * @inheritDoc
*/
public function &offsetGet( $offset ) {
$data = &$this->backend->getData();