}


    @Override
    public void waitForAllPendingCalls() {
        waitForAllPendingCalls(BlockingHttpServer.FailureTracker.NO_FAILURE_TRACKER);
    }

    @Override
    public void waitForAllPendingCalls(BlockingHttpServer.FailureTracker failureTracker) {
        lock.lock();
        try {
            previous.assertCanWait();

            long now = clock.getCurrentTime();

         * failure captured during execution which should be reported without waiting further.
         */
        void waitForAllPendingCalls(FailureTracker failureTracker);
    }

    public interface FailureTracker {
        FailureTracker NO_FAILURE_TRACKER = new FailureTracker() {
            @Override