@Override
        public Comparator<? super T> getComparator() {
            return source.getComparator();
        }
Returns the estimate size of this Spliterator.

Synchronized to get an accurate sum of <code>buffer.size()</code> and <code>source.estimateSize()</code>.
jOOL/src/main/java/org/jooq/lambda/SeqBuffer.java