@Override
    public void deleteAll(Collection<?> collection) throws CacheWriterException {
        long startNanos = Timer.nanos();
        try {
            delegate.get().deleteAll(collection);
        } finally {
            deleteAllProbe.recordValue(Timer.nanosElapsed(startNanos));
        }
    }
@Test
    public void deleteAll() {
        Collection<Object> c = new LinkedList<>();

        cacheWriter.deleteAll(c);

        verify(delegate).deleteAll(c);
        assertProbeCalledOnce("deleteAll");
    }