omg.diff

diff --git a/Gemfile b/Gemfile
index 97406be..96dc4fc 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ gem 'concurrent-ruby', '~> 1.0.0.pre3', github: 'ruby-concurrency/concurrent-rub
 
 # Active Job depends on the URI::GID::MissingModelIDError, which isn't released yet.
 gem 'globalid', github: 'rails/globalid', branch: 'master'
-gem 'rack', github: 'rack/rack', branch: 'master'
+gem 'rack', path: '/Users/aaron/git/rack'
 
 # This needs to be with require false as it is
 # loaded after loading the test library to
diff --git a/Gemfile.lock b/Gemfile.lock
index 7d6db04..486937f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -28,14 +28,6 @@ GIT
       mime-types (>= 1.16, < 3)
 
 GIT
-  remote: git://github.com/rack/rack.git
-  revision: c28f271d0c91f45e13bfa8f07bed445ef91f41de
-  branch: master
-  specs:
-    rack (2.0.0.alpha)
-      json
-
-GIT
   remote: git://github.com/rails/arel.git
   revision: 77ec13b46af2926bfcfc3073685711c874b0d272
   branch: master
@@ -167,6 +159,12 @@ PATH
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
 
+PATH
+  remote: /Users/aaron/git/rack
+  specs:
+    rack (2.0.0.alpha)
+      json
+
 GEM
   remote: https://rubygems.org/
   specs:
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index f6f63f1..19a6f8c 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -39,7 +39,7 @@ module ActionDispatch # :nodoc:
       end
 
       def []=(k,v)
-        if @response.committed?
+        if @response.sending? || @response.sent?
           raise ActionDispatch::IllegalStateError, 'header already sent'
         end
 
@@ -142,6 +142,9 @@ module ActionDispatch # :nodoc:
       super()
 
       @header = Header.new(self, header)
+      @header[Rack::RACK_HIJACK] = lambda { |io|
+        each { |chunk| io.write chunk }
+      }
 
       self.body, self.status = body, status
 
@@ -156,6 +159,10 @@ module ActionDispatch # :nodoc:
       yield self if block_given?
     end
 
+    def write(string)
+      @buffer << string
+    end
+
     def have_header?(key);  headers.key? key;   end
     def get_header(key);    headers[key];       end
     def set_header(key, v); headers[key] = v;   end
diff --git a/actionpack/lib/action_dispatch/journey/router.rb b/actionpack/lib/action_dispatch/journey/router.rb
index c570de2..d9f4879 100644
--- a/actionpack/lib/action_dispatch/journey/router.rb
+++ b/actionpack/lib/action_dispatch/journey/router.rb
@@ -39,7 +39,7 @@ module ActionDispatch
 
           req.path_parameters = set_params.merge parameters
 
-          status, headers, body = route.app.serve(req)
+          status, headers, body = route.app.serve(req, res)
 
           if 'pass' == headers['X-Cascade']
             req.script_name     = script_name
diff --git a/actionpack/lib/action_dispatch/middleware/cookies.rb b/actionpack/lib/action_dispatch/middleware/cookies.rb
index 2889aca..3149d46 100644
--- a/actionpack/lib/action_dispatch/middleware/cookies.rb
+++ b/actionpack/lib/action_dispatch/middleware/cookies.rb
@@ -589,6 +589,20 @@ module ActionDispatch
       @app = app
     end
 
+    def serve(request, res)
+      @app.serve request, res
+
+      if request.have_cookie_jar?
+        cookie_jar = request.cookie_jar
+        unless cookie_jar.committed?
+          cookie_jar.write(res.headers)
+          if res.headers[HTTP_HEADER].respond_to?(:join)
+            res.headers[HTTP_HEADER] = res.headers[HTTP_HEADER].join("\n")
+          end
+        end
+      end
+    end
+
     def call(env)
       request = ActionDispatch::Request.new env
 
diff --git a/actionpack/lib/action_dispatch/middleware/request_id.rb b/actionpack/lib/action_dispatch/middleware/request_id.rb
index 1555ff7..de760fb 100644
--- a/actionpack/lib/action_dispatch/middleware/request_id.rb
+++ b/actionpack/lib/action_dispatch/middleware/request_id.rb
@@ -18,6 +18,12 @@ module ActionDispatch
       @app = app
     end
 
+    def serve(req, res)
+      req.request_id = make_request_id(req.x_request_id)
+      res.set_header X_REQUEST_ID, req.request_id
+      @app.serve req, res
+    end
+
     def call(env)
       req = ActionDispatch::Request.new env
       req.request_id = make_request_id(req.x_request_id)
diff --git a/actionpack/lib/action_dispatch/middleware/stack.rb b/actionpack/lib/action_dispatch/middleware/stack.rb
index eea8bb1..4e05604 100644
--- a/actionpack/lib/action_dispatch/middleware/stack.rb
+++ b/actionpack/lib/action_dispatch/middleware/stack.rb
@@ -47,6 +47,7 @@ module ActionDispatch
           req = env['_REQUEST']
           res = env['_RESPONSE']
           app.serve req, res
+          [res.status, res.headers, Object.new]
         end
       end
 
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 74d9a53..23b7efb 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -26,10 +26,9 @@ module ActionDispatch
 
         def dispatcher?; true; end
 
-        def serve(req)
+        def serve(req, res)
           params     = req.path_parameters
           controller = controller req
-          res        = controller.make_response! req
           dispatch(controller, params[:action], req, res)
         rescue NameError => e
           if @raise_on_name_error
diff --git a/actionview/lib/action_view/digestor.rb b/actionview/lib/action_view/digestor.rb
index 12e9723..a643102 100644
--- a/actionview/lib/action_view/digestor.rb
+++ b/actionview/lib/action_view/digestor.rb
@@ -13,6 +13,11 @@ module ActionView
         ActionView::Digestor.cache.clear
         app.call(env)
       end
+
+      def serve(req, res)
+        ActionView::Digestor.cache.clear
+        app.serve(req, res)
+      end
     end
 
     class << self
diff --git a/activerecord/lib/active_record/query_cache.rb b/activerecord/lib/active_record/query_cache.rb
index dcb2bd3..2099e03 100644
--- a/activerecord/lib/active_record/query_cache.rb
+++ b/activerecord/lib/active_record/query_cache.rb
@@ -27,6 +27,19 @@ module ActiveRecord
       @app = app
     end
 
+    def serve(req, res)
+      connection    = ActiveRecord::Base.connection
+      enabled       = connection.query_cache_enabled
+      connection_id = ActiveRecord::Base.connection_id
+      connection.enable_query_cache!
+
+      res.after_finish do
+        restore_query_cache_settings(connection_id, enabled)
+      end
+
+      @app.serve req, res
+    end
+
     def call(env)
       connection    = ActiveRecord::Base.connection
       enabled       = connection.query_cache_enabled
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
index 4580f31..c8ed257 100644
--- a/railties/lib/rails/engine.rb
+++ b/railties/lib/rails/engine.rb
@@ -717,6 +717,7 @@ module Rails
     end
 
     def build_response(req)
+      ActionDispatch::Response.create
     end
 
     def build_middleware