Comment by the_othernet

Added the Romu variants to benchmark.c. Here are the current results:

LoopMix128 ns/call: 0.380 ns

xoroshiro128++ ns/call: 0.757 ns

wyrand ns/call: 0.379 ns

PCG64 ns/call: 0.757 ns

RomuQuad ns/call: 0.575 ns

RomuDuoJr ns/call: 0.416 ns