Method equal

include/boost/histogram/axis/iterator.hpp:35–37

    return other.idx_ - idx_;
  }
  bool equal(const iterator_over& other) const noexcept {
    return &axis_ == &other.axis_ && idx_ == other.idx_;
  }
  typename Axis::bin_type dereference() const { return axis_[idx_]; }
  friend class ::boost::iterator_core_access;