Re. the `def` - whoops. Thanks.

You need an evictable cache, or at least something to limit memory usage. The previous asset controller would effectively cache for every asset successfully served, with no bounds.

I can understand that you may *want* the size of the cache to be configurable, but I do not concur that it *needs* to be. I'm unsure of the *big* performance issues that you refer to, particularly considering that the existing implementation has two caches, doesn't cache gzip lookups and some other performance improvements introduced. I don't think we cared very much about performance there before.

Can we get confirmation on whether spray-cache is to disappear from the internet? spray-cache seems pretty useful to given that it returns futures and thus avoids the thundering-herds issue.

Re. Guava, Play already has that dependency so no new dependency is given.