# File lib/rack/response.rb, line 96
    def finish(&block)
      @block = block

      if [204, 304].include?(status.to_i)
        header.delete "Content-Type"
        [status.to_i, header.to_hash, []]
      else
        header["Content-Length"] ||= @length.to_s
        [status.to_i, header.to_hash, self]
      end
    end