@Override
    public void merge(Accumulator<Integer, Integer> other) {
        this.max = Math.max(this.max, other.getLocalValue());
    }
@Test
    void testMerge() {
        IntMaximum max1 = new IntMaximum();
        max1.add(1234);

        IntMaximum max2 = new IntMaximum();
        max2.add(5678);

        max2.merge(max1);
        assertThat(max2.getLocalValue().intValue()).isEqualTo(5678);

        max1.merge(max2);
        assertThat(max1.getLocalValue().intValue()).isEqualTo(5678);
    }