// TF_ImportGraphDefOptionsAddInputMapping() that didn't appear in the GraphDef
// and weren't used as input to any node in the imported graph def. The number
// of fetched mappings is returned in `num_missing_unused_input_mappings`. The
// array of each mapping's source node name is returned in `src_names`, and the
// array of each mapping's source index is returned in `src_indexes`.
//

  ///
  /// NOTE: The requirements specify that `TF_ALREADY_EXISTS` is not returned if
  /// directory exists. Similarly, `TF_NOT_FOUND` is not be returned, as the
  /// missing directory entry and all its descendants will be created by the
  /// plugin.
  ///
  /// DEFAULT IMPLEMENTATION: Creates directories one by one. Needs
  /// `path_exists`, `is_directory`, and `create_dir`.