func (osfs OSFileSystem) Open(p string) (io.ReadCloser, error) {
	return os.Open(p)
}
Open opens a file, it wraps os.Open
package nfs
import (
	"io"
	"os"
)
var DefaultFileSystem = OSFileSystem{}
type FileSystem interface {
	Open(string) (io.ReadCloser, error)
}
type OSFileSystem struct{}