public void incrementNumFailures() {
        if (!waiting) {
            numFailures.incrementAndGet();
        }
    }
Counters useful for measuring asynchronous requests. It is important for users to call
{@link #incrementCurrentRequests()} and {@link #decrementCurrentRequests()} at beginning and end of a
request to make sure all requests are completed before moving onto the next benchmark iteration.
benchmarks/jmh/src/jmh/java/com/linecorp/armeria/shared/AsyncCounters.java