code: func Uint32Zero(x uint32) uint32 {
  	h := prime32_5 + 4 + x*prime32_3
  	h = rol17(h) * prime32_4
  	h ^= h >> 15
  	h *= prime32_2
  	h ^= h >> 13
  	h *= prime32_3
  	h ^= h >> 16
  	return h
  }
docs: // Uint32Zero hashes x with seed 0.