stats/src/main/java/io/airlift/stats/cardinality/HyperLogLog.java
public void addHash(long hash)
    {
        instance.insertHash(hash);

        if (instance instanceof SparseHll) {
            instance = makeDenseIfNecessary((SparseHll) instance);
        }
    }
public void addHash(long hash)
    {
        instance.insertHash(hash);

        if (instance instanceof SparseHll) {
            instance = makeDenseIfNecessary((SparseHll) instance);
        }
    }
Adds a value that has already been hashed to the set of values tracked by this HyperLogLog instance.

@param hash The hash should be the 64 least significant bits of the murmur3_128 hash of the value.
For example: io.airlift.slice.Murmur3.hash64(value).