init shared memory buffer for async operations

src/Interface/Model/Buffer.php

@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yggverse\Yoda\Interface\Model;
+
+/*
+ * Shared memory API for async operations
+ *
+ */
+interface Buffer
+{
+    public function get(
+        string $key
+    ): mixed;
+
+    public function set(
+        string $key,
+        mixed $value
+    ): void;
+}