@Override
    public void writeAll(Collection<Cache.Entry<? extends K, ? extends V>> collection) throws CacheWriterException {
        long startNanos = Timer.nanos();
        try {
            delegate.get().writeAll(collection);
        } finally {
            writeAllProbe.recordValue(Timer.nanosElapsed(startNanos));
        }
    }
@Test
    public void writeAll() {
        Collection<Cache.Entry<? extends Integer, ? extends String>> c = new LinkedList<>();

        cacheWriter.writeAll(c);

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