Description:
------------
If you have a new class extends an ArrayObject, it will display a warning if you implement the __unserialize method with the type hinting of the first parameter:

Warning: Declaration of Collection::__unserialize(array $data): void should be compatible with ArrayObject::__unserialize($serialized) 

Test script:
---------------
	class Collection extends \ArrayObject
	{
		public function __serialize(): array
		{
			return $this->getArrayCopy();
		}

		public function __unserialize(array $data): void
		{
			$this->__construct($data);
		}
	}
	$collection = new Collection([
		'name' => 'Hello World',
		'path' => [
			'of' => [
				'the' => 'Road',
				'number' => 20,
				'text_a' => '    Bad Boy!',
				'text_b' => 'Good Boy!   ',
			],
		],
	]);

	$s1 = serialize($collection);
	var_dump($s1);
	$s2 = unserialize($s1);
	var_dump($s2);

Expected result:
----------------
string(195) "O:16:"Razy\CCollection":2:{s:4:"name";s:11:"Hello World";s:4:"path";a:1:{s:2:"of";a:4:{s:3:"the";s:4:"Road";s:6:"number";i:20;s:6:"text_a";s:12:" Bad Boy!";s:6:"text_b";s:12:"Good Boy! ";}}}"

object(Razy\CCollection)#66 (1) { ["storage":"ArrayObject":private]=> array(2) { ["name"]=> string(11) "Hello World" ["path"]=> array(1) { ["of"]=> array(4) { ["the"]=> string(4) "Road" ["number"]=> int(20) ["text_a"]=> string(12) " Bad Boy!" ["text_b"]=> string(12) "Good Boy! " } } } }

Actual result:
--------------
Warning: Declaration of Collection::__unserialize(array $data): void should be compatible with ArrayObject::__unserialize($serialized) in ...

string(195) "O:16:"Razy\CCollection":2:{s:4:"name";s:11:"Hello World";s:4:"path";a:1:{s:2:"of";a:4:{s:3:"the";s:4:"Road";s:6:"number";i:20;s:6:"text_a";s:12:" Bad Boy!";s:6:"text_b";s:12:"Good Boy! ";}}}"

object(Razy\CCollection)#66 (1) { ["storage":"ArrayObject":private]=> array(2) { ["name"]=> string(11) "Hello World" ["path"]=> array(1) { ["of"]=> array(4) { ["the"]=> string(4) "Road" ["number"]=> int(20) ["text_a"]=> string(12) " Bad Boy!" ["text_b"]=> string(12) "Good Boy! " } } } }