private void stopBackgroundHerder() throws Exception {
        herder.stop();
        herderExecutor.shutdown();
        assertTrue(herderExecutor.awaitTermination(10, TimeUnit.SECONDS), "herder thread did not finish in time");
        herderFuture.get();
        assertTrue(noneConnectorClientConfigOverridePolicy.isClosed());
    }
Issues multiple rapid fencing requests for a handful of connectors, each of which takes a little while to complete.
This mimics what might happen when a few connectors are reconfigured in quick succession and each task for the
connector needs to hit the leader with a fencing request during its preflight check.
connect/runtime/src/test/java/org/apache/kafka/connect/runtime/distributed/DistributedHerderTest.java