# File lib/em-http/client.rb, line 134
    def build_request
      head    = @req.headers ? munge_header_keys(@req.headers) : {}

      if @conn.connopts.http_proxy?
        proxy = @conn.connopts.proxy
        head['proxy-authorization'] = proxy[:authorization] if proxy[:authorization]
      end

      # Set the cookie header if provided
      if cookie = head['cookie']
        @cookies << encode_cookie(cookie) if cookie
      end
      head['cookie'] = @cookies.compact.uniq.join("; ").squeeze(";") unless @cookies.empty?

      # Set connection close unless keepalive
      if !@req.keepalive
        head['connection'] = 'close'
      end

      # Set the Host header if it hasn't been specified already
      head['host'] ||= encode_host

      # Set the User-Agent if it hasn't been specified
      if !head.key?('user-agent')
        head['user-agent'] = 'EventMachine HttpClient'
      elsif head['user-agent'].nil?
        head.delete('user-agent')
      end

      # Set the Accept-Encoding header if none is provided
      if !head.key?('accept-encoding') && req.compressed
        head['accept-encoding'] = 'gzip, compressed'
      end

      # Set the auth from the URI if given
      head['Authorization'] = @req.uri.userinfo.split(/:/, 2) if @req.uri.userinfo

      head
    end