func (badRootFS) Root() (fs.Node, fuse.Error) {
	// pick a really distinct error, to identify it later
	return nil, fuse.Errno(syscall.ENAMETOOLONG)
}
func (f customErrNode) Lookup(name string, intr fs.Intr) (fs.Node, fuse.Error) {
	return nil, myCustomError{
		ErrorNumber: fuse.Errno(syscall.ENAMETOOLONG),
	}
}
func (f *open) Open(req *fuse.OpenRequest, resp *fuse.OpenResponse, intr fs.Intr) (fs.Handle, fuse.Error) {
	f.Opens.Open(req, resp, intr)
	// pick a really distinct error, to identify it later
	return nil, fuse.Errno(syscall.ENAMETOOLONG)

}