to_s (PDF::Writer::Object::Outline)

        # File lib/pdf/writer/object/outline.rb, line 22
    22:   def to_s
    23:     pos = @parent.outlines.list.index(self)
    24:     res = "\n#{@oid} 0 obj\n<< /Title (#{@title})"
    25:     res << " /Prev #{@parent.outlines.list[pos - 1].oid} 0 R" if pos.nonzero?
    26:     res << " /Next #{@parent.outlines.list[pos + 1].oid} 0 R" if @oid != parent.outlines.list[-1].oid
    27:     res << " /A #{@action.oid} 0 R>>\nendobj"
    28:     res
    29:   end