Implement state

src/State.php

@@ -8,5 +8,33 @@ namespace Cerbero\JsonParser;
  */
 class State
 {
-    //
+    /**
+     * The JSON tree.
+     *
+     * @var Tree
+     */
+    public Tree $tree;
+
+    /**
+     * Whether the tree changed.
+     *
+     * @var bool
+     */
+    public bool $treeChanged = false;
+
+    /**
+     * The JSON buffer.
+     *
+     * @var string
+     */
+    public string $buffer = '';
+
+    /**
+     * Instantiate the class.
+     *
+     */
+    public function __construct()
+    {
+        $this->tree = new Tree();
+    }
 }