implement magic serializable methods

tests/Stateful/ObjectStorageTest_testClasses.php

@@ -167,6 +167,14 @@ namespace Grifart\Collection {
 		}
 
 
+		public function __unserialize(array $data): void
+		{
+			[$values, $keys] = $data;
+			$this->values = $values;
+			$this->keys = $keys;
+		}
+
+
 		public function serialize(): string
 		{
 			return \serialize([
@@ -176,6 +184,15 @@ namespace Grifart\Collection {
 		}
 
 
+		public function __serialize(): array
+		{
+			return [
+				$this->values,
+				$this->keys,
+			];
+		}
+
+
 		//<editor-fold desc="\ArrayAccess interface">
 		public function offsetExists($key): bool
 		{