find.go
func Find(dir string) *FindFilter {
	return &FindFilter{
		dir:       dir,
		ifmode:    func(os.FileMode) bool { return true },
		skipdirif: func(d string) bool { return false },
	}
}
func Find(dir string) *FindFilter {
	return &FindFilter{
		dir:       dir,
		ifmode:    func(os.FileMode) bool { return true },
		skipdirif: func(d string) bool { return false },
	}
}
// Find returns a filter that produces matching nodes under a
// filesystem directory. The items yielded by the filter will be
// prefixed by dir. E.g., if dir contains subdir/file, the filter
// will yield dir/subdir/file. By default, the filter matches all types
// of files (regular files, directories, symbolic links, etc.).
// This behavior can be adjusted by calling FindFilter methods
// before executing the filter.