# File lib/rack/deflater.rb, line 11
  def call(env)
    status, headers, body = @app.call(env)

    request = Request.new(env)

    encoding = Utils.select_best_encoding(%w(gzip deflate identity), request.accept_encoding)

    case encoding
    when "gzip"
      mtime = headers["Last-Modified"] || Time.now
      [status, headers.merge("Content-Encoding" => "gzip"), self.class.gzip(body, mtime)]
    when "deflate"
      [status, headers.merge("Content-Encoding" => "deflate"), self.class.deflate(body)]
    when "identity"
      [status, headers, body]
    when nil
      message = "An acceptable encoding for the requested resource #{request.fullpath} could not be found."
      [406, {"Content-Type" => "text/plain"}, message]
    end
  end