diff --git a/src/Client.php b/src/Client.php
index 8a06dc5..5dfddfb 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -237,7 +237,7 @@ public function download(array $options)
             'headers' => [
                 'Authorization' => $this->authToken,
             ],
-            'sink'    => isset($options['SaveAs']) ? $options['SaveAs'] : null,
+            'sink'    => isset($options['SaveAs']) ? $options['SaveAs'] : fopen('php://temp', 'w'),
         ];
 
         if (isset($options['FileId'])) {