# File lib/rack/response.rb, line 19
    def initialize(body=[], status=200, header={}, &block)
      @status = status
      @header = Utils::HeaderHash.new({"Content-Type" => "text/html"}.
                                      merge(header))

      @writer = lambda { |x| @body << x }
      @block = nil
      @length = 0

      @body = []

      if body.respond_to? :to_str
        write body.to_str
      elsif body.respond_to?(:each)
        body.each { |part|
          write part.to_s
        }
      else
        raise TypeError, "stringable or iterable required"
      end

      yield self  if block_given?
    end