code: def kill!(url)
        # normalize the url
        url = URI(url)
  
        # session key
        key = key_for(url)
  
        if (sess = @sessions[key])
          begin 
            sess.finish
          rescue IOError
          end
  
          @sessions.delete(key)
        end
      end
docs: Destroys an HTTP session for the given scheme, host and port.
  
   @param [URI::HTTP, String] url
     The URL of the requested session.
  
   @return [nil]
  
   @since 0.2.2