Implementd isCancelled method in Response class

Author: vuongxuongminh

src/Message/Response.php

@@ -26,6 +26,14 @@ public function isSuccessful(): bool
         return '1' === $this->getCode();
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function isCancelled(): bool
+    {
+        return '-9' === $this->getCode();
+    }
+
     /**
      * {@inheritdoc}
      */