func (fs FS) Path(p ...string) string {
	return path.Join(append([]string{string(fs)}, p...)...)
}
Path returns the path of the given subsystem relative to the procfs root.
package procfs
import (
	"fmt"
	"os"
	"path"
)
type FS string
const DefaultMountPoint = "/proc"
func NewFS(mountPoint string) (FS, error) {
	info, err := os.Stat(mountPoint)
	if err != nil {
		return "", fmt.Errorf("could not read %s: %s", mountPoint, err)
	}
	if !info.IsDir() {
		return "", fmt.Errorf("mount point %s is not a directory", mountPoint)
	}
	return FS(mountPoint), nil
}