keep_back

# File lib/csv/parser.rb, line 148
      def keep_back
        start, buffer = @keeps.pop
        if buffer
          string = @scanner.string
          keep = string.byteslice(start, string.bytesize - start)
          if keep and not keep.empty?
            @inputs.unshift(StringIO.new(keep))
            @last_scanner = false
          end
          @scanner = StringScanner.new(buffer)
        else
          @scanner.pos = start
        end
        read_chunk if @scanner.eos?
      end