public static Builder custom() {
        return new Builder();
    }
@Test
    public void buildTimeoutDurationIsNotWithinLimits() {
        exception.expect(ThrowableCauseMatcher.hasCause(isA(ArithmeticException.class)));
        exception.expectMessage("TimeoutDuration too large");
        RateLimiterConfig.custom()
            .timeoutDuration(Duration.ofSeconds(Long.MAX_VALUE));
    }