public CacheConfig build() {
            final CacheConfig cacheConfig = new CacheConfig(
                    maximumSize,
                    expireAfterAccess,
                    expireAfterWrite,
                    refreshAfterWrite,
                    statisticsMode);
            NullSafe.consume(basePath, cacheConfig::setBasePath);
            return cacheConfig;
        }
Uses Dropwizard Metrics for capturing statistics. This allows the cache stats
to be accessed via tools such as Graphite/Collectd in addition to the Stroom UI.
This is suitable for both Stroom and Stroom-Proxy.
This adds a very slight performance overhead over {@link StatisticsMode#INTERNAL}.
stroom-util/src/main/java/stroom/util/cache/CacheConfig.java