When performance is a thing, a small cache can make a big difference. Nichecache is a thread-safe generic cache with FIFO replacement policy: [https://github.com/olliNiinivaara/Nichecache](https://github.com/olliNiinivaara/Nichecache)
It's a fine example of algorithm that looks bad in theory (brute-force looping over all keys) but in practice is hard to beat for small cache sizes due to it's cache-friendliness (CPUs use caches, too). With 50 lines of code (not counting comments and tests), it's a pretty elegant data structure. Must have something to do with the programming language I am using!
