code: func seedHash(block uint64) []byte {
  	seed := make([]byte, 32)
  	if block < epochLength {
  		return seed
  	}
  	keccak256 := makeHasher(sha3.NewLegacyKeccak256())
  	for i := 0; i < int(block/epochLength); i++ {
  		keccak256(seed, seed)
  	}
  	return seed
  }
docs: // seedHash is the seed to use for generating a verification cache and the mining
  // dataset.