public void completeExceptionally(Throwable t) {
            Objects.requireNonNull(t);
            fencingFollowup.onCompletion(t, null);
        }
Fail the fencing if it is still active, reporting the given exception as the cause of failure
@param t the cause of failure to report for the failed fencing; may not be null
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/distributed/DistributedHerder.java