This method returns an array with four elements containing information about how the child widget is packed. Index 0 contains the expand value for the widget where 0 is false and 1 is true. Index 1 contains the fill value for the widget where 0 is false and 1 is true. Index 2 contains the padding value for the widget as an integer of the number of pixels of padding. Index 3 contains the pack_type value for the widget: either Gtk::PACK_START or Gtk::PACK_END