@TearDown(Level.Iteration)
        public void clear() {
            // SPSC -> consumer must clear the queue
            end.clear();
        }
We want to always start with an empty inbound. Iteration tear downs are synchronized.
jctools-benchmarks/src/main/java/org/jctools/jmh/latency/spsc/RingCqBurstRoundTripWithGroups.java