Join using regular separators on the client, not OS-specific ones

walk.go

@@ -42,7 +42,7 @@ func (c *Client) walk(path string, walkFn filepath.WalkFunc) error {
 
 	sort.Strings(names)
 	for _, name := range names {
-		err = c.walk(filepath.Join(path, name), walkFn)
+		err = c.walk(filepath.ToSlash(filepath.Join(path, name)), walkFn)
 		if err != nil {
 			return err
 		}