This is a fixed-increment version of Java 8's SplittableRandom generator. It is a very fast generator passing BigCrush, and can be useful if for some reason exactly 64 bits of state are needed; otherwise, it is suggested to use Xoroshiro128plus (for moderately parallel computations) or Xorshift1024star (for massively parallel computations).
Implementation of the SplitMix64 uniform random number generator.