contribute
abstract fun <E : Extension> contribute(extensionPoint: ExtensionPoint<E>, plugin: Plugin, extensionInstance: E)
注册一个扩展
abstract fun <E : Extension> contribute(extensionPoint: ExtensionPoint<E>, plugin: Plugin, lazyInstance: () -> E)
注册一个扩展. lazyInstance 将会在 getExtensions 时才会计算.