feat: add public $context

Author: kenjis

system/Test/PhpStreamWrapper.php

@@ -22,6 +22,13 @@
  */
 final class PhpStreamWrapper
 {
+    /**
+     * @var resource|null The current context.
+     *
+     * See https://www.php.net/manual/en/class.streamwrapper.php#streamwrapper.props.context
+     */
+    public $context;
+
     private static string $content = '';
     private int $position          = 0;