Check data existence

Message/RequestAbstract.php

@@ -217,6 +217,20 @@ abstract class RequestAbstract implements MessageInterface
         return $this->data[$key] ?? null;
     }
 
+    /**
+     * Check if has data.
+     *
+     * @param mixed $key Data key
+     * 
+     * @return bool
+     *
+     * @since  1.0.0
+     */
+    public function hasData($key) : bool
+    {
+        return isset($this->data[$key]);
+    }
+
     /**
      * Set request data.
      *