public static Builder newBuilder() {
        return new Builder();
    }
@Test
    public void successOverflow() {
        AIMDLimit limiter = AIMDLimit.newBuilder().initialLimit(21).maxLimit(21).minLimit(0).build();
        limiter.onSample(0, TimeUnit.MILLISECONDS.toNanos(1), 10, false);
        // after success limit should still be at the max.
        Assert.assertEquals(21, limiter.getLimit());
    }