given:
        withParallelThreads(2)
        buildFile << """
            def dir = rootProject.file("dir")

            aPing.destroyables.register dir

            bPing.outputs.file dir
        """

        expect:
        2.times {
            blockingServer.expectConcurrent(1, ":aPing", ":bPing")
            run ":aPing", ":bPing"

    }

    private
    suspend fun WriteContext.writeDestroyablesOf(task: TaskInternal) {
        val destroyables = (task.destroyables as TaskDestroyablesInternal).registeredFiles
        if (destroyables.isEmpty) {
            writeBoolean(false)
        } else {
            writeBoolean(true)
            write(destroyables)
        }
    }

    private
    suspend fun ReadContext.readDestroyablesOf(task: TaskInternal) {

     *
     * @return The outputs. Never returns null.
     */
    @Internal
    TaskOutputs getOutputs();

    /**
     * <p>Returns the destroyables of this task.</p>
     * @return The destroyables.  Never returns null.
     *
     * @since 4.0
     */
    @Internal
    TaskDestroyables getDestroyables();

    /**
     * Returns the local state of this task.
     *