Status IsDirectory(const std::string& fname,
                     TransactionToken* token) override;
  Status GetFileSize(const std::string& fname, TransactionToken* token,
                     uint64* file_size) override;
  Status RenameFile(const std::string& src, const std::string& target,
                    TransactionToken* token) override;
  Status CopyFile(const std::string& src, const std::string& target,

  ///     points to a directory.
  ///   * Might use any other error value for `status` to signal other errors.
  ///
  /// DEFAULT IMPLEMENTATION: Gets statistics about `path`. Needs `stat`.
  int64_t (*get_file_size)(const TF_Filesystem* filesystem, const char* path,
                           TF_Status* status);

  /// Translates `uri` to a filename for the filesystem
  ///