delete (MemCache)

    # File lib/active_support/vendor/memcache-client-1.7.4/memcache.rb, line 474
      def delete(key, expiry = 0)
        raise MemCacheError, "Update of readonly cache" if @readonly
        with_server(key) do |server, cache_key|
          with_socket_management(server) do |socket|
            logger.debug { "delete #{cache_key} on #{server}" } if logger
            socket.write "delete #{cache_key} #{expiry}#{noreply}\r\n"
            break nil if @no_reply
            result = socket.gets
            raise_on_error_response! result
            result
          end
        end
      end