// In header: <boost/date_time/time_zone_base.hpp>
template<typename time_duration_type> 
class dst_adjustment_offsets {
public:
  // construct/copy/destruct
  dst_adjustment_offsets(const time_duration_type &, 
                         const time_duration_type &, 
                         const time_duration_type &);
  // public data members
  time_duration_type dst_adjust_;  // Amount DST adjusts the clock eg: plus one hour. 
  time_duration_type dst_start_offset_;  // Time past midnight on start transition day that dst starts. 
  time_duration_type dst_end_offset_;  // Time past midnight on end transition day that dst ends. 
};