def generate_loader_url(idx, cache_last_modified)
      # FIXME: Escape variables
      url = "https://www.google.com/m8/feeds/contacts/#{@user}/thin"
      url += '?orderby=lastmodified'
      url += '&showdeleted=true'
      url += "&max-results=#{@fetch_size}"
      url += "&start-index=#{idx}"
      if cache_last_modified
        url += "&updated-min=#{CGI.escape(cache_last_modified)}"
      end
      url
    end
def generate_loader_url(idx, cache_last_modified)
      # FIXME: Escape variables
      url = "https://www.google.com/m8/feeds/contacts/#{@user}/thin"
      url += '?orderby=lastmodified'
      url += '&showdeleted=true'
      url += "&max-results=#{@fetch_size}"
      url += "&start-index=#{idx}"
      if cache_last_modified
        url += "&updated-min=#{CGI.escape(cache_last_modified)}"
      end
      url
    end
Generate the URL to retrieve the next chunk of data from GMail.

 @param [Integer] idx Index of next piece of data to read from
   <tt>client</tt>.
 @param [Datetime] cache_last_modified modification time of last contact
   read from GMail