/// Returns pointer to an array of available configuration options and their
  /// current/default values in `options` and number of options in array in
  /// `num_options`. Ownership of the array is transferred to caller and the
  /// caller is responsible of freeing the buffers using respective file systems
  /// allocation API.
  ///
  /// Plugins:
  ///   * Must set `status` to `TF_OK` if `options` and `num_options` set.

  ///    placed in `out`.
  /// 4) `TF_OK` otherwise (i.e. the read succeeded, and at least one byte was
  /// placed
  ///    in `buffer`).
  ///
  /// Caller is responsible for allocating memory for `buffer`.
  /// `buffer` will be left unchanged in case of errors.
  int64_t Read(const std::string& filename, size_t offset, size_t n,
               char* buffer, TF_Status* status);