cumulativeUnionLine(output, hll, emptyHLL, schemaVersion);
for(int i=0; i<EXPLICIT_THRESHOLD; i++) {
// make an EXPLICIT set and populate with cardinality 1
final HLL explicitHLL = newHLL(HLLType.EXPLICIT);
explicitHLL.addRaw(random.nextLong());
// union it into the accumulator twice, to test overlap (cardinality should not change)
cumulativeUnionLine(output, hll, explicitHLL, schemaVersion);
cumulativeUnionLine(output, hll, explicitHLL, schemaVersion);
}