add Err field to Pager structure
diff --git a/pagination/pager.go b/pagination/pager.go
index 806d98a..cc1c048 100644
--- a/pagination/pager.go
+++ b/pagination/pager.go
@@ -35,6 +35,8 @@
 
 	createPage func(r LastHTTPResponse) Page
 
+	Err error
+
 	// Headers supplies additional HTTP headers to populate on each paged request.
 	Headers map[string]string
 }