private static int fmix(int h1, int length) {
        h1 ^= length;
        h1 ^= h1 >>> 16;
        h1 *= 0x85ebca6b;
        h1 ^= h1 >>> 13;
        h1 *= 0xc2b2ae35;
        h1 ^= h1 >>> 16;
        return h1;
    }
32-bit Murmur3 hasher.  This is based on Guava's Murmur3_32HashFunction.
indexr-common/src/main/java/io/indexr/util/Hasher32.java