# File lib/edi4r.rb, line 355
    def to_s( postfix='' )
      s = @header ? @header.to_s+postfix : ''
      each {|obj| s << (obj.is_a?(Segment) ? obj.to_s+postfix : obj.to_s)}
      s << @trailer.to_s+postfix if @trailer
      s
    end