apply plugin: SomePlugin

            abstract class ListenerImpl implements BuildService<BuildServiceParameters.None>, OperationCompletionListener {
                void onFinish(FinishEvent event) {
                    // Only generic task details are exposed for now
                    assert !(event.result instanceof JavaCompileTaskOperationResult)
                }
            }

    override val sharedIdentities = ReadIdentities()

    private
    var singletonProperty: Any? = null

    override lateinit var classLoader: ClassLoader

    override fun onFinish(action: () -> Unit) {
        pendingOperations.add(action)
    }

    fun finish() {
        for (op in pendingOperations) {
            op()
        }
        pendingOperations.clear()
    }

    suspend fun read(): Any?

    fun readClass(): Class<*>

    /**
     * Defers the given [action] until all objects have been read.
     */
    fun onFinish(action: () -> Unit)

    fun <T : Any> getSingletonProperty(propertyType: Class<T>): T
}


inline
fun <reified T : Any> ReadContext.getSingletonProperty(): T =
    getSingletonProperty(T::class.java)