Use finish_with_state inside Rack::Logger

This ensures that the finish instrumenter is sent to the same
subscribers that the initial request was sent to.

This solves an issue where in a threaded environment the dynamic
subscriptions from ActionDispatch::ServerTiming would cause a mismatch
in the number of subscriptions to a topic, which would pop too many
values off of the thread-local stacks, leading to invalid events being
sent to subscribers.

Fixes rails#44167

Author: jhawthorn

railties/lib/rails/rack/logger.rb

@@ -31,13 +31,17 @@ def call(env)
       private
         def call_app(request, env) # :doc:
           instrumenter = ActiveSupport::Notifications.instrumenter
-          instrumenter.start "request.action_dispatch", request: request
+          instrumenter_state = instrumenter.start "request.action_dispatch", request: request
+          instrumenter_finish = -> () {
+            instrumenter.finish_with_state(instrumenter_state, "request.action_dispatch", request: request)
+          }
+
           logger.info { started_request_message(request) }
           status, headers, body = @app.call(env)
-          body = ::Rack::BodyProxy.new(body) { finish(request) }
+          body = ::Rack::BodyProxy.new(body, &instrumenter_finish)
           [status, headers, body]
         rescue Exception
-          finish(request)
+          instrumenter_finish.call
           raise
         ensure
           ActiveSupport::LogSubscriber.flush_all!
@@ -65,11 +69,6 @@ def compute_tags(request) # :doc:
           end
         end
 
-        def finish(request)
-          instrumenter = ActiveSupport::Notifications.instrumenter
-          instrumenter.finish "request.action_dispatch", request: request
-        end
-
         def logger
           Rails.logger
         end