instrument

# File activesupport/lib/active_support/cache.rb, line 511
        def instrument(operation, key, options = nil)
          log(operation, key, options)

          if self.class.instrument
            payload = { :key => key }
            payload.merge!(options) if options.is_a?(Hash)
            ActiveSupport::Notifications.instrument("cache_#{operation}.active_support", payload){ yield(payload) }
          else
            yield(nil)
          end
        end