public override int ReadDir(ReadOnlySpan <byte> path, ulong offset, ReadDirFlags flags, DirectoryContent content, ref FuseFileInfo fi)
 => ReadDir(ToString(path), offset, flags, content, ref fi);
 protected virtual int ReadDir(string path, ulong offset, ReadDirFlags flags, DirectoryContent content, ref FuseFileInfo fi)
 => - ENOSYS;
 public virtual int ReadDir(ReadOnlySpan <byte> path, ulong offset, ReadDirFlags flags, DirectoryContent content, ref FuseFileInfo fi)
 => - ENOSYS;