count number of active record objects instantiated

instrumentation.rb

ActiveSupport::Notifications.subscribe "instantiation.active_record" do |*args|
  event = ActiveSupport::Notifications::Event.new(*args)
  RequestStore.store[:object_count] ||= 0
  RequestStore.store[:object_count] += event.payload[:record_count]
end

ActiveSupport::Notifications.subscribe "process_action.action_controller" do
  Rails.logger.info "AR Object count: #{RequestStore.store[:object_count]}"
end