private static Cache<PathAndEncoding, AggregatedHttpFile> newCache(String cacheSpec) {
        final Caffeine<Object, Object> b = Caffeine.from(cacheSpec);
        b.recordStats()
         .removalListener((RemovalListener<PathAndEncoding, AggregatedHttpFile>) (key, value, cause) -> {
             if (value != null) {
                 final HttpData data = value.content();
                 if (data != null) {
                     data.close();
                 }
             }
         });
        return b.build();
    }
Returns a new {@link FileServiceBuilder} with the specified {@link HttpVfs}.
core/src/main/java/com/linecorp/armeria/server/file/FileService.java