Use response_body rather than performed?

actionpack/lib/action_controller/base.rb

@@ -41,7 +41,7 @@ class Base < Metal
     module ImplicitRender
       def send_action(*)
         ret = super
-        default_render unless performed?
+        default_render unless response_body
         ret
       end
 

actionpack/test/template/body_parts_test.rb

@@ -4,7 +4,7 @@ class BodyPartsTest < ActionController::TestCase
   RENDERINGS = [Object.new, Object.new, Object.new]
 
   class TestController < ActionController::Base
-    def performed?() true end
+    def response_body() "" end
 
     def index
       RENDERINGS.each do |rendering|