presto-main/src/main/java/io/prestosql/operator/aggregation/TypedSet.java/TypedSet/isContainedAt
class TypedSet:    private boolean isContainedAt(Block block, int position, int atPosition)
    {
        if (elementIsDistinctFrom.isPresent()) {
            boolean firstValueNull = elementBlock.isNull(atPosition);
            Object firstValue = firstValueNull ? defaultValue(elementType.getJavaType()) : readNativeValue(elementType, elementBlock, atPosition);
            boolean secondValueNull = block.isNull(position);
            Object secondValue = secondValueNull ? defaultValue(elementType.getJavaType()) : readNativeValue(elementType, block, position);
            try {
                return !(boolean) elementIsDistinctFrom.get().invoke(firstValue, firstValueNull, secondValue, secondValueNull);
            }
            catch (Throwable t) {
                throw internalError(t);
            }
        }
        return positionEqualsPosition(elementType, elementBlock, atPosition, block, position);
    }