public RandomVariant31(UInt64 seed)
 {
     s_0 = RandomSplitMix64.Next(ref seed);
     s_1 = RandomSplitMix64.Next(ref seed);
 }
 public RandomXoroshiro128plus(UInt64 seed)
 {
     s_0 = RandomSplitMix64.Next(ref seed);
     s_1 = RandomSplitMix64.Next(ref seed);
 }