Second argument to track() should be either file or directory resource

create the command in laravel 8
```
$watcher = new ResourceWatcher;
$watcher->track('folder.watch', 'doc_file/',FilesystemEvent::CREATE);

```
but when supervisor run got below error 
```
Lurker\Exception\InvalidArgumentException
  Second argument to track() should be either file or directory resource, but got "doc_files/"
```
**"doc_files"** is the folder under storage folder  
  