# File lib/rack/file.rb, line 24
    def initialize(root, headers={})
      @root = root
      # Allow a cache_control string for backwards compatibility
      if headers.instance_of? String
        warn \
          "Rack::File headers parameter replaces cache_control after Rack 1.5."
        @headers = { 'Cache-Control' => headers }
      else
        @headers = headers
      end
    end