# File multipart.rb, line 49
      def initialize(filepath_or_io,
                     mimetype='application/octet-stream',
                     filename=nil)
        @mimetype = mimetype
        @filename = nil

        if filepath_or_io.respond_to? :read
          @input = filepath_or_io
          @shouldclose = false # came opened

          if filepath_or_io.respond_to? :path
            @filename = File.basename(filepath_or_io.path)
          end

        else
          @input = File.open(filepath_or_io, 'rb')
          @shouldclose = true # I opened it
          @filename = File.basename(filepath_or_io)
        end

      end