///   * Must set `status` to `TF_NOT_FOUND` if one of the parents entries in
  ///     either `src` or `dst` doesn't exist or if the specified `src` path
  ///     doesn't exist.
  ///   * Must set `status` to `TF_FAILED_PRECONDITION` if either `src` or
  ///     `dst` is a directory or if either of them is invalid.
  ///   * Might use any other error value for `status` to signal other errors.
  ///