add getter for protected headers property

flight/net/Response.php

@@ -145,6 +145,14 @@ class Response {
         return $this;
     }
 
+    /**
+     * Returns the headers from the response
+     * @return array
+     */
+    public function headers() {
+        return $this->headers;
+    }
+
     /**
      * Writes content to the response body.
      *