Is a (*Cache).Sync() method desirable?

[hraban]

Synchronizing the cache (waiting for all pending operations to complete) is a nice thing for the unit tests, but I never need it outside a testing scenario. Should it be part of the public interface of a cache? I am undecided..

[hraban]

If this is implemented, pay special attention to pending onmiss calls. The current implementation of syncCache in the tests only works because it is executed by the same goroutine as the ones issuing a possibly missing Get.