code: function (h) {
        h = x64Xor(h, [0, h[0] >>> 1])
        h = x64Multiply(h, [0xff51afd7, 0xed558ccd])
        h = x64Xor(h, [0, h[0] >>> 1])
        h = x64Multiply(h, [0xc4ceb9fe, 0x1a85ec53])
        h = x64Xor(h, [0, h[0] >>> 1])
        return h
      }
docs: Given a block, returns murmurHash3's final x64 mix of that block. (`[0, h[0] >>> 1]` is a 33 bit unsigned right shift. This is the only place where we need to right shift 64bit ints.)