Constant keccak_hash::KECCAK_EMPTY

pub const KECCAK_EMPTY: H256 = H256([197, 210, 70, 1, 134, 247, 35, 60, 146, 126, 125, 178, 220, 199, 3, 192,
      229, 0, 182, 83, 202, 130, 39, 59, 123, 250, 216, 4, 93, 133, 164, 112])

Get the KECCAK (i.e. Keccak) hash of the empty bytes string.