to_json (DateTime)

        # File lib/json/add/core.rb, line 64
    64:   def to_json(*args)
    65:     {
    66:       'json_class' => self.class.name,
    67:       'y' => year,
    68:       'm' => month,
    69:       'd' => day,
    70:       'H' => hour,
    71:       'M' => min,
    72:       'S' => sec,
    73:       'of' => offset.to_s,
    74:       'sg' => start,
    75:     }.to_json(*args)
    76:   end