code: func (f *FolderConfiguration) CheckPath() error {
  	fi, err := f.Filesystem().Stat(".")
  	if err != nil {
  		if !fs.IsNotExist(err) {
  			return err
  		}
  		return ErrPathMissing
  	}
  
  	// Users might have the root directory as a symlink or reparse point.
  	// Furthermore, OneDrive bullcrap uses a magic reparse point to the cloudz...
  	// Yet it's impossible for this to happen, as filesystem adds a trailing
  	// path separator to the root, so even if you point the filesystem at a file
  	// Stat ends up calling stat on C:\dir\file\ which, fails with "is not a directory"
  	// in the error check above, and we don't even get to here.
  	if !fi.IsDir() && !fi.IsSymlink() {
  		return ErrPathNotDirectory
  	}
  
  	_, err = f.Filesystem().Stat(f.MarkerName)
  	if err != nil {
  		if !fs.IsNotExist(err) {
  			return err
  		}
  		return ErrMarkerMissing
  	}
  
  	return nil
  }
docs: // CheckPath returns nil if the folder root exists and contains the marker file