@hugares, I think that is wrong implementation. @Extension annotated classes are still not registered before Plugin.postInitialize() phase. See PluginManager.initTasks() in Jenkins core.

This plugin has Plugin inherited class. In this case, plugin registration process is:

* `Loading plugin`
  * Register instance of Plugin subclass (PluginImpl)
  * Plugin.start()
* `Initializing plugin`
  * Plugin.postInitialize()
* `Discovering plugin initialization tasks`
  * Register instances of @Extension annotated class

PluginManager runs the above process on each plugins. So, force initialization for ReplicationQueueTaskDispatcher might not be done even if QueueTaskDispatcher.all() is called in Plugin.postInitialize().

Perhaps lazy load scheduling is plugin-by-plugin.