collection: Introduce TwoQueueCache.
collection: Introduce TwoQueueCache.

A scan-resistant caching algorithm.

See https://pdfs.semanticscholar.org/d62d/e5f995164fff50f5ce61c0113f6bc9f04225.pdf.
and http://people.cs.vt.edu/~butta/docs/sigmetrics05_kernelPrefetch.pdf

GSGroup/stingraykit,GSGroup/stingraykit