createOrModifyTag
fun <T : Keyed> LifecycleEventManager<BootstrapContext>.createOrModifyTag(tag: TagKey<T>, priority: Int = 0, modify: TagBuilder.Paper<T>.() -> Unit)
Registers a pre-flatten LifecycleEvents.TAGS handler that applies modify to tag, creating a new tag if it does not exist yet. The builder is run again on every tag reload. Changes to providers supplied to this builder cause a data reload.