Merge pull request #305 from PDoakORNL/fix_hdf5_chemical_potential_read

   *  file may have multiple iterations in it.

   *  Each iteration is a step in the adios file for many variables.

   */

  std::size_t getStepCount() { return file_.Steps(); }

  long getStepCount() { return file_.Steps(); }

  // `execute` returns true if the object is read correctly.

  std::string get_path() const;

  std::size_t getStepCount();

  long getStepCount();

  template <typename arbitrary_struct_t>

  static void from_file(arbitrary_struct_t& arbitrary_struct, std::string file_name);

  void open_file(std::string file_name_ref, bool overwrite = true);

  void close_file();

  void legacy_close_file();

  bool open_group(std::string new_path);

  void close_group();

  // the root group.

  bool close_group() noexcept;

  std::size_t getStepCount() { return 0; }

  long getStepCount() { return 0; }

  std::string get_path() { return {}; }

    std::visit([&](auto& var) { var.close_group(); }, reader_);

  }

  std::size_t getStepCount() {

  long getStepCount() {

    return std::visit([&](auto& var) ->std::size_t { return var.getStepCount(); }, reader_);

  }