Add unloader for EventManager

To handle zeitwerk autoloader

Author: lorenyu

app/helpers/flex/event_manager.rb

@@ -1,5 +1,7 @@
 module Flex
   class EventManager
+    @@subscriptions = []
+
     class << self
       def subscribe(event_key, callback)
         subscription = ActiveSupport::Notifications.subscribe(event_key) do |name, _started, _finished, _unique_id, payload|
@@ -9,13 +11,21 @@ def subscribe(event_key, callback)
           })
         end
 
+        @@subscriptions << subscription
         subscription
       end
 
       def unsubscribe(subscription)
         ActiveSupport::Notifications.unsubscribe(subscription)
       end
 
+      def unsubscribe_all
+        @@subscriptions.each do |subscription|
+          ActiveSupport::Notifications.unsubscribe(subscription)
+        end
+        @@subscriptions.clear
+      end
+
       def publish(event_key, payload = {})
         Rails.logger.debug "Event Manager: Publishing event '#{event_key}' with payload: #{payload.inspect}"
         ActiveSupport::Notifications.instrument(event_key, payload)

lib/flex/engine.rb

@@ -11,5 +11,11 @@ class Engine < ::Rails::Engine
     initializer "flex.previews" do |app|
       config.lookbook.preview_paths << Flex::Engine.root.join("app", "previews") if config.respond_to?(:lookbook)
     end
+
+    config.after_initialize do
+      Rails.autoloaders.main.on_unload("Flex::EventManager") do |klass|
+        klass.unsubscribe_all
+      end
+    end
   end
 end