///
  /// After this call `file` may be concurrently accessed by multiple threads.
  ///
  /// Plugins:
  ///   * Must set `status` to `TF_OK` if `file` was updated.
  ///   * Must set `status` to `TF_NOT_FOUND` if `path` doesn't point to an
  ///     existing file or one of the parent entries in `path` doesn't exist.