<key>\x00[<version>]<#version-bytes>.

MVCCKeyCompare compares two MVCC keys.

SplitMVCCKey accepts an MVCC key and returns the "user" key, the MVCC version, and a boolean indicating if the provided key is an MVCC key.

TODO: Make configurable.

s/k:<storeKey>.

MVCCComparer returns a PebbleDB Comparer with encoding and decoding routines for MVCC control, used to compare and store versioned keys.

For writing kv pairs in any order of version.