vendor and env first commit

vendor/maennchen/zipstream-php/src/Zs/ExtendedInformationExtraField.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ZipStream\Zs;
+
+use ZipStream\PackField;
+
+/**
+ * @internal
+ */
+abstract class ExtendedInformationExtraField
+{
+    private const TAG = 0x5653;
+
+    public static function generate(): string
+    {
+        return PackField::pack(
+            new PackField(format: 'v', value: self::TAG),
+            new PackField(format: 'v', value: 0x0000),
+        );
+    }
+}