//   use them in new code.
// - Every node in the function's body must have all of its inputs (including
//   control inputs). In other words, for every node in the body, each input
//   must be either listed in `inputs` or must come from another node in
//   the body. In particular, it is an error to have a control edge going from

  ///     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.
  ///