public int hashInt(int input) {
        int k1 = mixK1(input);
        int h1 = mixH1(seed, k1);

        return fmix(h1, 4);
    }
32-bit Murmur3 hasher.  This is based on Guava's Murmur3_32HashFunction.
indexr-common/src/main/java/io/indexr/util/Hasher32.java