class Rack::Files::BaseIterator

def each
  ::File.open(path, "rb") do |file|
    ranges.each do |range|
      yield multipart_heading(range) if multipart?
      each_range_part(file, range) do |part|
        yield part
      end
    end
    yield "\r\n--#{MULTIPART_BOUNDARY}--\r\n" if multipart?
  end
end